What is the smallest angle $($in degrees$)$ with respect to the normal that light should be incident onto awater$-$air interface from the water side so that it does not escape into air assume the refractive index ofwater is $1\mathrm{.}33)?$

O $20$

O $10\mathrm{.}5$

O $48\mathrm{.}8$

O $50\mathrm{.}2$