Question

78. The sum of n terms of the series n.1+(n-1).2+(n-2).37 .-**** 15
(a) (1/6)(n+1)(n+2) (6) (1/3)(n+1)(1+2) (c) (1/2)(1+1)(1+2)​

Answer 1

option a is correct

by putting value of n= 1 or 2 in both answer and question so option 1 match