A casting of a square prism is shown in the Figure. Estimate the time in 'hours', to cool the casting using Chvorinov's rule, (ts = B(V/A)n). the mold constant is one and the exponent is 2 when the time is in hour, volume is in cm3 and surface area is in cm2.
A. 9 hrs
B. 36 hrs
C. 3 hrs
D. 12 hrs