The total sales of S (in thousands of DVD's) of a certain movie are given by the following ionnuia where t is the number of months since the release of the DVD. Use the formula to answer the questions. 3) Find S'(t). 8'0) = [I b) Find 5(20) and S'(20). The value of 8(20) rounded to the nearest hundredth is D. The value of S'(20) rounded to the nearest hundredth is D. What do the values for 8(20) and 3120) indicate? 0 A. After 20 months, the total sales are 14,400 DVD's and the sales are increasing at the rate 017200 DVD's per month. 0 B. Alter 20 months. the total sales are 72,000 DVD's and the sales are increasing at the rate of 1.44 DVD's per month. 0 C. Alter 20 months, the total sales are 72,000 DVD's and the sales are increasing at the rate at 1440 DVDs per month. 0 D. After 20 months, the total sales are 1440 DVD's and the sales are increasing at the rate of 72 DVD's per month. c) Use the results from part (b) to estimate the total sales after 21 months. Atter 21 months, the total sales will be approximately how many DVD's? El (Round to the nearest whole number.)