What is the area of a square, of the length of any of its sides is 3.5cm?

a. 3.5cm2
b. 7cm2
c. 10.5cm2
d. 12.25 cm2

I believe the answer is d 3.5 x 3.5

Right.

3.5 * 3.5 = 12.25 square centimeters