[单选题]
A plano-convex lens is to hazx/x ,cy;f,bjvio- vr8l)b2t ve a focal lengty q3c8x-bh0bye n 8s lc4zf;sj.i72clh of 40 cm. It is made of glass of index of refractionzc fsj 072xl;nq ybsyc3cble 8-8.4ih 1.65. What radius of curvature is required?
A. $13 \; cm$
B. $26 \; cm$
C. $32 \; cm$
D. $36 \; cm$
