Sea turtle hatchlings leaving their hatching grounds on Florida beach

On Inference questions, quickly identify and toss out the outside-the-scope and too-broad choices.

Let’s boil it down. Hatchlings both wild and domestic (i.e. in the tank) swim northeast, in the context of Earth’s normal magnetic field. But when that field is doubled and set in the opposite direction, hatchlings swim in that opposite direction.

That strongly supports (C), the idea that the hatchlings can somehow sense Earth’s magnetism. If you wrestled with that, consider how far wrong the other choices go:

(A) The scope is the hatchlings’ direction, not their habits upon reaching the end of their swim.
(B) never mentions sea turtle hatchlings. Moreover, the situation here is the hatchlings’ reaching ocean currents, not the source of those currents.
(D) Nothing in the (D) mentions a return by any sea turtles, baby or adult.
(E) is a very peculiar prediction utterly unsupported by the text. If anything, since no magnetic change is imposed in (E), the (E) suggests an inference that turtles, wherever they hatch, will travel in a northeast direction exclusively. So (E) is way off in several respects.