TOEFL Reading: ETS-TOEFL阅读机经 - L5VHL89T65U31581L$

In paragraph 5, why does the author provide the information that hatchling green sea turtles can navigate around small islands and keep swimming offshore even when few waves are present? A. To point out a benefit of the fact that hatchlings use their geomagnetic compasses almost as soon as they leave the nest B. To provide evidence that green sea turtles use different navigational techniques than leatherbacks and olive ridley turtles do C. To provide a reason for considering the possibility that sea turtles navigate by detecting Earth's magnetic field D. To provide evidence showing that hatchling do not automatically follow their geomagnetic compass if other cues are available