Solve the Problem. -The Weekly Sales in Thousands of Items of a Product

Multiple Choice

Solve the problem.
-The weekly sales in thousands of items of a product has a seasonal sales record approximated by n = 72.04 + 18.9 sin (t = time in weeks with t=1 referring to the first week in the year) . During which week(s) will the sales equal
81,490 items?

A) week 4, week 20, and week 52
B) week 30 and week 47
C) week 21 and week 30
D) week 4 and week 47