Answer:
84
Step-by-step explanation:
I believe the answer is B.
A has fixed one time fee of $12 and if you go to it say "m" months you pay $28 for each month, so your total cost at A is really 12 + 28m.
B has a fixed one time fee of $20 and if you go to it "m" months you pay $26 for each month, so you total cost at B is 20 + 26m.
how many months for the cost to be the same?

well, since the cost for both is the same, we can just get A's, knowing that B is the same

Please ask the question in English, if you are not able to, I believe you are in the wrong language section and suggest you try something else before you get your question taken down.