The edge of a cube is 2a cm. Find its surface?  Select the correct option
A) 23 a 2 cm 2	B) 84 a 2 cm 2	C) 64 a 2 cm 2	D) 24 a 2 cm 2	E) 14 a 2 cm 2

Rationale: "6 a 2 = 6 * 2 a * 2 a = 24 a 2 answer : d"
Answer: D