Q: Fact 1: Earth 's magnetic patterns are used for finding locations by animals that migrate. Fact 2: Animated maps show the birds flying along their actual migration paths. Given the two facts above, earth's magnetic patterns are used so that birds can fly along their what?

OPT:
[A]. migrating pain;
[B]. migration paths;
[C]. our nearest star;
[D]. flying schedule;
[E]. Something to move;
[F]. travel plans;
[G]. important habitats;
[H]. their hosts;
A:
[B].