Discuss the differentiability of $f\left(x\right)=\max \left\{{\sec }^{-1}x,\cos e{c}^{-1}x\right\}$

Not Differentiable at x = 2 

Differentiable at x = $\sqrt{2}$

Differentiable  at x = 2 

Not Differentiable at x = $\sqrt{2}$