A= 20th term of 1.2+2.3+3.4+…. B=15th term of 1.3+3.5+5.7+… C=10th term of 1.22+2.32+3.42+… D=10th term of 2.12+3.22+4.32+…. Then the increasing order of A, B, C, D is
A. A, B, C, D
B. A, C, D, B
C. A, B, D, C
D. A,D, B, C
1.22+2.32+3.4+….+n(n+1)2=
A. n(n+1)(n+2)(3n+5)/12
B. n(n+1)(n+2)(n+3)/4
C. 2n(n+1)(n+2)(n+3)
D. n(n+1)(n+2)(3n+1)/12