Evaluations for input

A 14-in-diameter hollow sphere of steel (SG = 7.85) has 0.16 in wall thickness. How much weight must be added inside to make the sphere neutrally buoyant? <image 1>

(A) 15 lbf

(B) 50 lbf

(C) 25 lbf

Answer with the option's letter from the given choices directly. No punctuation.