A Small Economy Has Only Two Consumers, Zeke and Maude

A small economy has only two consumers, Zeke and Maude. Zeke's utility function is U(x, y) . Maude's utility function is U(x, y) = x + 4y. At a Pareto optimal allocation in which both individuals consume some of each good, how much y does Zeke consume?

A) 36
B) 12
C) 5
D) 10
E) We can't tell without knowing the initial endowments.