Which customers would benefit most from purchasing a Sender Authentication Package (SAP)?

A: A growing consumer brand that expects to send 500,000 emails per month and would like email branding to be consistent with its domain, B: A nonprofit organization that sends roughly 50,000 newsletter emails per month. C: A growing retailer that currently leverages Marketing Cloud's MobileConnect and MobilePush. D: A customer who wants to share another IP within their account structure and is unconcerned about branding at this time.