Answer:
It's A!
Explanation:
Basically, I substituted numbers in and added the per-month cost and per-visit cost:
Ann: 25 Blake: 33 (1 visit)
Ann: 30 Blake: 36 (2 visits)
Ann: 35 Blake: 39 (3 visits)
Ann: 40 Blake: 42 (4 visits)
Ann: 45 Blake: 45 (5 visits)