theoretical length of a bar

Question

A 10 mm thick steel bar is to be horizontally cast with two correctly spaced top risers of adequate feeding capacity. Assuming end effect without chill, what should be the theoretically length of the bar?

(a) 96 mm                           (b) 132 mm

(c) 192 mm                         (d) 156 mm

Comments

Sir ,plz provide solution of this ques