The correct option is C Neither maximum nor minimum at x=0
Let f(x)=x5−5x4+5x3−1
⇒f′(x)=5x4−20x3+15x2=0
∴(x−3)(x−1)=0 , x =0,3,1
Now f′′(x)=20x3−60x2+30x
Put x=3 and 1, we get f"(3) =+ve and f"(1) =-ve and f"(0) =0.Hence f(x) neither maximum nor minimum at x=0.