If y=\log \cos x^{2} then \frac{d y}{d x} at x=\sqrt{x} has the value (a) 1 (b) \frac{\pi}{4} (c) 0 (d) \sqrt{\pi}
If y=\log \cos x^{2} then \frac{d y}{d x} at x=\sqrt{x} has the value (a) 1 (b) \frac{\pi}{4} (c) 0 (d) \sqrt{\pi}

SOL;
Correct option is (c) 0