C is the answer!! I hope this helps!!!
Answer:

Step-by-step explanation:

40/50 is the ratio because the cos formula is adjacent over hypotenuse and you can reduce it to 4/5 as a fraction :)
An exponential behavior can be observed.
Let x be the number of years she has to wait.
100((1+0.08/12)^12x) = 150
Now solve for x.
log base 1.08/12 of 1.5 = 61.02 approx
12x=61.02
x=5.09 years