The correct option is C (√x3)23
Simplify each option:
Option A, x127−x57 cannot be simplified further, hence it is not equal to x
Option B, 12√(x4)13 on simplifying is equal to, x19
Option C, (√x3)23 on simplifying is equal to, x
Option D, x127×x712 on simplifying is equal to, x19384