What single transformation maps ∆ABC onto ∆A'B'C'?

A. rotation 90° clockwise about the origin
B. rotation 90° counterclockwise about the origin
C. reflection across the x-axis
D. reflection across the line y = x

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm