Answer:
The correct option is: a. 21 inches
Explanation:
The area of the rectangle is 357 square inches and width is 17 inches.
Formula for the area of rectangle is:

Suppose, the length of the rectangle
inches.
So, the equation will be.....
![357=x* 17\\ \\ (357)/(17)=(x* 17)/(17)\ [Dividing\ both\ sides\ by\ 17]\\ \\ 21=x](https://img.qammunity.org/2018/formulas/mathematics/high-school/ugva4w03wtr9012f6g3c4h23ihf4pb2neh.png)
So, the rectangle is 21 inches long.