Question

A

Answer 1

@ganeshie8

Answer 2

@OpiGeode

Answer 3

No.

Answer 4

please note that:
\[2u\left( {1 - {u^2}} \right) + 2u\left( {1 + {u^2}} \right) = 2u - 2{u^3} + 2u + 2{u^3} = ...?\]