[单选题]
Light enters a substance fro *cckae+z 8*3ezmb2fro7m4mab 9 mco: m air at6:sl ayh+0btm $30.0^{\circ}$ to the normal. It continues through the substance at $23.0^{\circ}$ to the normal. What would be the critical angle for this substance?
A. $53.0^{\circ}$
B. $51.4^{\circ}$
C. $36.7^{\circ}$
D. $12.6^{\circ}$
