You have one pile of 10 building blocks, each one a different color, and you also have another pile of 6 blocks, again each one a different color. How many ways are there to build a tower 4 blocks...

Please help me with this math homework question. I really can not figure this out.

Extracted text: You have one pile of 10 building blocks, each one a different color, and you also have another pile of 6 blocks, again each one a different color. How many ways are there to build a tower 4 blocks high from the first pile and another tower 2 blocks high from the second pile? Assume that the colors at each level of a tower matter. (A) C(10, 4) · C(6, 2) (B) C(16,6) (C) 216 (D) C(10,4)+C(6,2) (E) P(16,6) (F) P(10,4) · P(6, 2) (G) P(10, 4) + P(6, 2) (H) 210 O A C E F H