Explanation
To begin troubleshooting the issue of data not being up to date from Sales Cloud, the Marketing Cloud admin should go to Contact Builder > Data Sources. Data Sources is a page that allows NTO to manage their data sources and integrations in Contact Builder. NTO can use Data Sources to check the status and settings of their Sales Cloud integration, such as the sync frequency, sync direction, sync filters, and sync errors. The other options are incorrect because:
* Contact Builder > Data Extensions > Synchronized Data Extensions. This is a folder that contains all the synchronized data extensions in Marketing Cloud. Synchronized data extensions are data extensions that store the data from synced Sales Cloud Objects in Marketing Cloud. However, this folder does not allow NTO to troubleshoot their Sales Cloud integration; it only shows the data extensions that are created by the sync process.
* Automation Studio > File Transfers. This is a page that allows NTO to view and manage their file transfer activities in Automation Studio. File transfer activities are activities that move files from one location to another, such as from an FTP site to the Safehouse or from the Safehouse to a data extension.
However, this page does not allow NTO to troubleshoot their Sales Cloud integration; it only shows the file transfer activities that are created by NTO.
* Email Studio > Synchronized Data Extensions. This is a page that allows NTO to view and manage their synchronized data extensions in Email Studio. Synchronized data extensions are data extensions that store the data from synced Sales Cloud Objects in Marketing Cloud. However, this page does not allow NTO to troubleshoot their Sales Cloud integration; it only shows the data extensions that are created by the sync process.

Explanation
The admin should create separate business units for each of NTO's brands when brand-specific private domains need to be leveraged when wrapping images and links in email campaigns. A private domain is a domain name that NTO owns and uses for their email sends, such as email.nto.com. A private domain can be used to wrap images and links in emails to improve deliverability and branding. However, a private domain can only be associated with one business unit in Marketing Cloud, so NTO needs to create separate business units for each brand that requires a different private domain2. The other options are incorrect because:
* NTO requires SSL certificate configurations for Content Builder and Portfolio images. This is not a reason to create separate business units for each brand, as SSL certificate configurations can be applied
* at the account level or the business unit level. SSL certificates are used to secure the connection between NTO's web server and their subscribers' browsers, and can be applied to Content Builder or Portfolio images to ensure they are delivered over HTTPS3.
* Multiple brand logos must be accommodated in an email header. This is not a reason to create separate business units for each brand, as multiple brand logos can be accommodated in an email header using dynamic content or AMPscript. Dynamic content or AMPscript are features that allow NTO to display different content in their emails based on subscriber attributes or data extension fields4.
* A new sender profile needs to be leveraged for sending transactional emails. This is not a reason to create separate business units for each brand, as a new sender profile can be created and leveraged within the same business unit. A sender profile is a configuration that defines the sender information for an email, such as the from name, from address, reply address, and sender classification5.