If 6 parallel lines in a plane is intersected by a family of another 8 parallel lines, how many parallelograms are there in the network thus formed?  Pick one: A) 80 B) 63 C) 420 D) 160 E) 1260

Rationale: "parallelogram can formed by 2 horizontal and 2 vertical lines for horizontal 6 c 2 for vertical 8 c 2 total parallelogram is 6 c 2 * 8 c 2 = 15 * 28 = 420 answer : c"
Answer: C