Dynamic lists are lists that automatically add or remove prospects based on criteria that you define. Prospects can be "unmatched" from a dynamic list if they no longer meet the criteria. For example, if you have a dynamic list of prospects who have opened an email in the last 30 days, and a prospect does not open any email for 31 days, they will be removed from the list. Automation rules and segmentation rules do not "unmatch" prospects, they only apply actions to prospects that match the criteria

Explanation
According to the [Salesforce documentation], the best way to accomplish the scenario of sending out an email to a list of prospects that are assigned to several different sales reps, and having each prospect receive the email from their assigned rep, is to select Assigned User for the Sender of the email. This option will use the email address and name of the user who is assigned to the prospect in Salesforce or Marketing Cloud Account Engagement as the sender of the email. This way, the email will appear more personalized and relevant to the prospect, and will increase the chances of engagement and response. Selecting General User, Account Owner, or Specified User will not achieve the same result, as they will use a generic, fixed, or predefined sender for the email, regardless of the prospect's assigned user. References: [Salesforce documentation]

Explanation
A form handler setting that allows prospects to receive multiple autoresponders from form submissions within a 24-hour period is Disable Visitor Activity Throttling and send autoresponder emails after every submission. This setting overrides the default behavior of Marketing Cloud Account Engagement, which is to throttle visitor activity and send only one autoresponder email per prospect per form per day2. This setting can be useful for forms that are used for multiple purposes, such as event registration, content download, or contact request

Explanation
The administrator should go to Admin-Domain Management to check if the Email Sending Domains are set up properly after updating the DNS. Email Sending Domains are domains that you can use to send emails from Marketing Cloud Account Engagement, and they require verification and authentication to ensure that your emails are delivered and not marked as spam. To verify and authenticate your Email Sending Domains, you need to update the DNS records of your domain with the values provided by Marketing Cloud Account Engagement. After updating the DNS, you can go to Admin-Domain Management and click the Verify Now button to check if your Email Sending Domains are verified and authenticated

Explanation
Marketing Cloud Account Engagement can sync with Salesforce custom fields that are on the Lead, Contact, or Account objects. Custom Prospect fields in Marketing Cloud Account Engagement can be mapped to custom Lead or Contact fields in Salesforce. Custom Account fields in Marketing Cloud Account Engagement can be mapped to custom Account fields in Salesforce. Custom Opportunity fields in Marketing Cloud Account Engagement can be mapped to custom Opportunity fields in Salesforce. Custom Record Type fields are not supported by Marketing Cloud Account Engagement and cannot be synced