Manuel Insists He Places an Infinite Value on His Life

Manuel insists he places an infinite value on his life. Stefan is suspicious of this claim and points out to Manuel that he sometimes eats ice cream when broccoli would be much better for him. What Big Idea is Stefan using?

A) The Power of Trade: Manuel could not make his own ice cream, though he could grow his own broccoli; Manuel must be trading for ice cream.
B) Incentives: No one is paying Manuel to be healthy.
C) Thinking on the Margin: "Infinite value" is too much to be on the margin.
D) Trade-offs: Gaining some enjoyment is worth giving up some safety.