[单选题]
A double convex (convex-conve);gu mz3e8hp mx)y cytwlwd u+a0.36o) v thin lens has radii of curvature 46 cm, and is made of glass of index of refraction n = 1.60. What isu6 yd ow)0vc.+wl tya3 the focal length?
A. infinite
B. $38 \; cm$
C. $30 \; cm$
D. $18 \; cm$
