[单选题]
Lucite has an index of refraction of 1.dy c+s(5av m,jmicv ,1;9xa td50. What ito18beuws* ih 74:7es;s do*x h rm0ocs its critical angle of incidences:x8s*bo 4oteo0 h*h;7si w u1dc7rm e?
A. $11.6^{\circ}$
B. $15.4^{\circ}$
C. $41.8^{\circ}$
D. $87.4^{\circ}$
