The answer to the question is c
The sine increases from 0 to 90 degrees and from 270 to 360 degrees
The sine decreases from 90 to 270 degrees
The cosine increases from 180 to 360 degrees
The cosine decreases from 0 to 180 degrees
Sine = 0 at 0 and 180 degrees
Cosine = 0 at 90 and 270 degrees
amount after 2 years = 6000(1 + (0.04/12))^24 = 6498.86