Answer: Without other information, the number of animals maybe between 19-73 depending on age and pancreas size. Of the options presented, the nearest answer is D.32
Explanation: Assumptions
2yo cow with pancreas 400g
insulin content ~5 IU (175ug)
Daily insulin requirement 0.5-1 IU —> 187-365 IU p.a.
beef animals required 37-73 cows
using 6 mo calves, the insulin content is ~10IU, so requiring 19-37 calves