In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").
Q: Fact1: Wings are part of the exoskeleton and attached to the thorax., Fact2: Butterflies bask to heat up their wing muscles for flight., Question: What organism's instruments of flight are part of the exoskeleton and attached to the thorax? (A) insects (B) organs (C) barnacles (D) butterflies (E) to move people (F) honeybees (G) it needs them (H) Electric devices
A:
D