Explanation
The two ways that a Marketing Cloud Account Engagement prospect syncs with a Salesforce Lead or Contact record are shared CRM ID and shared email address. A CRM ID is a unique identifier that is assigned to a Lead or Contact record in Salesforce and is synced with the corresponding prospect record in Marketing Cloud Account Engagement. A CRM ID ensures that the prospect data is matched with the correct Lead or Contact data and prevents duplicates. A CRM ID is created when a prospect is created or updated in Marketing Cloud Account Engagement and a matching Lead or Contact is found or created in Salesforce, or when a Lead or Contact is created or updated in Salesforce and a matching prospect is found or created in Marketing Cloud Account Engagement5. An email address is a required field for both a prospect in Marketing Cloud Account Engagement and a Lead or Contact in Salesforce. An email address is used to identify and associate a prospect with a Lead or Contact, and to trigger a sync between Marketing Cloud Account Engagement and Salesforce. An email address is also used to track the prospect's activities, such as email opens, clicks, form submissions, and page views5. Option B is not correct because a shared assigned user ID is not a way that a Marketing Cloud Account Engagement prospect syncs with a Salesforce Lead or Contact record, but a result of the sync. An assigned user ID is the ID of the user who owns the prospect in Marketing Cloud Account Engagement or the Lead or Contact in Salesforce. The assigned user ID is synced between Marketing Cloud Account Engagement and Salesforce to ensure that the same user owns the prospect and the Lead or Contact, unless there are custom assignment rules in place5. Option D is not correct because a shared tracking pixel is not a way that a Marketing Cloud Account Engagement prospect syncs with a Salesforce Lead or Contact record, but a method of tracking the prospect's activities. A tracking pixel is a hidden image that is embedded in an email or a web page and sends a request to Marketing Cloud Account Engagement's server when the email or the web page is opened. A tracking pixel allows Marketing Cloud Account Engagement to record the prospect's email opens, page views, and other actions

Explanation
A completion action on a custom redirect will be triggered when an existing prospect clicks on the custom redirect. A custom redirect is a trackable link that can be used to measure the engagement of prospects with external content, such as a website, a PDF, or a video. A completion action is an automated task that can be performed after a prospect takes a certain action, such as clicking on a custom redirect. Completion actions for custom redirects will only apply to existing prospects, meaning prospects who have already been identified by Marketing Cloud Account Engagement through a form, a landing page, or an email4. References: Marketing Cloud Account Engagement Custom Redirects

Explanation
The best way to be able to track the number of visitors who access a file on a web page that the company does not own is to use a custom redirect. A custom redirect is a Marketing Cloud Account Engagement feature that allows you to track any link on your website or a third-party website and measure the clicks and conversions.
You can create a custom redirect for the link to the file and use the custom redirect URL instead of the original link on your web page. This way, you can track how many visitors click on the link and access the file, and also see which prospects are interested in the file. A Marketing Cloud Account Engagement form, a Marketing Cloud Account Engagement tracking code, or a page action are not suitable for this purpose, as they are used for different scenarios. A Marketing Cloud Account Engagement form is used to collect visitor information and convert them to prospects. A Marketing Cloud Account Engagement tracking code is used to track the page views and activities of visitors and prospects on your own website. A page action is used to perform certain actions when a prospect views a specific page on your website. References Custom Redirects

Explanation
The reason why the email link www.lenoxsoft.com was not re-written for tracking is that the link should start with http or https to be automatically re-written. Marketing Cloud Account Engagement automatically re-writes links in emails to track the clicks and measure the engagement of the recipients. However, Marketing Cloud Account Engagement only re-writes links that start with http or https, as these are the protocols that indicate a web address. The link www.lenoxsoft.com does not have a protocol, so Marketing Cloud Account Engagement does not recognize it as a web address and does not re-write it for tracking. The other options are not relevant for link re-writing. The link does not need to contain a wildcard, point to go.Marketing Cloud Account Engagement.com, or be populated with variable tags to be automatically re-written. These are features that can be used to create dynamic or custom links, but they are not required for link re-writing. References [Link Click Tracking]

For a Salesforce Opportunity to sync to Marketing Cloud Account Engagement, the Opportunity must have a Contact Role that is syncing to a prospect in Marketing Cloud Account Engagement. This means that the Contact Role must be associated with a Contact record that has a Marketing Cloud Account Engagement prospect record. The Opportunity record type, source, or creator are not relevant for the sync1