The weekly sales in thousands of items of a product has a seasonal sales record approximated by n= 84.59 + 24.8 sin (t is time in weeks with t = 1 referring to the first week in the year). during which week(s) will the sales equal 96,990 items? a. week 21 and week 30b. week 4 and week 47c. week 4, week 20, and week 52d. week 30 and week 47