Which one of the following functions has a discontinuty in the second derivative at x = 0, whre x is a real variable? (a) f(x) = |x (b) f(x) = x\x (c) f(x) = co

Which one of the following functions has a discontinuty in the second derivative at x = 0, whre x is a real variable? (A) f(x) = |x (B) f(x) = x\x (C) f(x) = cos (X|) (D) f(x) = Ix|3