Subject: mathqa
Question: joan took out a mortgage from hel local bank . each monthly mortgage payment she makes must be triple the amount of the previous month ' s payment . if her first payment is $ 100 , and the total amount she must pay back is $ 36400 , how many months will it take joan to pay back her mortgage ?
Option: 
A: 6
B: 8
C: 11
D: 13
Answer: A