一束自然光从空气投射到玻璃表面上,当折射角为30°时,反射光为完全偏振光,则此玻璃板的折射率为( )。
A A.2 B
B.3 C
C.<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818028_0.png"> D
D.<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818028_0_1.png">