17. [11 Points] DETAILS 0i100 Submissions Used The total monthly revenue R(X} generated from sales of Math tshirts is related to the amount x spent on advertising by R[x)= 3x3 + 18x2 63X + 30 where X is in thousands of dollars and [is X S 1-0. Which one of the following statements is true? 0 $1000 is a point of diminishing returns. 0 $1000 is a point of increasing returns. 0 $2000 is a point of diminishing returns. 0 There are no points of increasing or diminishing returns. 0 $2000 is a point of increasing returns