The 2nd, 3rd and 4th terms in the expansion of (x+y)n are 240, 720 and 1080 respectively. Find x, y, n.

A. n = 4, x = 2, y = 3
B. n = 5, x = 2, y = 3
C. n = 4, x = 3, y = 3
D. n = 6, x = 2, y = 3