Answer:

(the third answer in your list of options)
Explanation:
The area of the region between y = x, and the x axis, between x= 3 and x=6 is the area of the trapezoid shown in the attached image.
It therefore can be calculated via the area of a trapezoid:

or doing the integral (which it seems is what they want you to do):
![\int\limits^6_3 {x} \, dx =(x^2)/(2) ]\limits^6_3=(6^2-3^2)/(2) =(27)/(2)](https://img.qammunity.org/2021/formulas/mathematics/college/sk47ik4bska3iydnu6sf3zywpghyz5ki6q.png)