Which of the following is NOT true about mathematical induction? A. The first possible case is always n = 1.

B. Mathematical induction depends on a recursive process.

C. It can be used to prove that 1 + 2 + 3+...+n =
n(n+2)
2

D. Since Sn is valid for n = 1, it is valid for n = 2. Since it is valid for n = 2, it is valid for n = 3, and so on, indefinitely.​