What is the benefit of using a reference block instead of AMP Script within a template based email in Content Builder?

Northern Trail Outfitters (NTO) is launching a custom, corporate-branded apparel website. They are concerned about the new initiative's campaign impacting deliverability on its consumer retail sends. NTO has purchased a second IP address to be used for the corporate site's email sending.
What feature would be used to specify which IP address is used for retail vs. corporate?

A customer would like to automate a weekly email campaign using Automation Studio. Which send method would the customer use to configure the email?

Northern Trail Outfitters (NTO) has child business units that share customers. To track customer engagement. NTO wants to identify business unit in each of its links.
Which personalization string should be appended as a parameter?
A)

B)

C)

Northern Trait Outfitters is using a Smart Capture form on a CloudPage to capture contest registrations in a data extension. Corporate has requested a nightly file with all registrants in this data extension be sent daily from Marketing Cloud to an external SFTP.
Which automation configuration should be used to achieve this?