In the Sierra Nevada Mountains of California There Are Many

In the Sierra Nevada mountains of California there are many populations of the checkerspot butterfly, Euphydryas editha. The young of both populations hatch out as caterpillars; they live on the host plant and eat the new leaves. The host plant used by population A grows over a single season, with new leaves (the most nutritious) appearing at the tip of the stem. Where do you expect females from population A to lay their eggs?

A) at the base of the plant stem
B) at the tip of the plant stem
C) anywhere along the plant stem
D) in the exact middle of the plant stem