The coefficients corresponding to k = 0, 1, 2, ..., 6 in the expansion of (x + y)6
are
A. 0, 6, 15, 20, 15, 6, 0
B. 1, 6, 15, 15, 6, 1
C. 1, 6, 15, 20, 15, 6, 1
D. 0, 1, 6, 15, 15, 6, 1,0