What should they be aware of with respect to sender reputation?

Northern Trail Outfitters upgraded their Marketing Cloud account which now includes a Sender Authentication Package (SAP), They send regularly 300,000

What should they be aware of with respect to sender reputation?
A . They should have one dedicated IP address for every 100,000 messages send per month.
B. They should have a shared IP since their volume is under 500,000 messages per month.
C. They should have one SAP for transactional sends and another for commercial sends.
D. They should send at least 250,000 messages per month to maintain their sender reputation.

Answer: D