Evidence without increases its reliability.
bias
question
repetition
replication

I would say your answer is question, mostly because when your proving something with evidence then you start asking questions (or still have questions) makes it seem like you don't really know. Therefore it's not very reliable.

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.