Teacher: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").
Teacher: Now, understand the problem? Solve this instance: Fact1: the vanes rotating in an electric fan causes air to move, Fact2: Output of the fan is varied by means of a series of adjustable vanes upstream of the impeller., Question: what is fan speed? (A) energy barrier (B) kinetic energy (C) fixed (D) cycles (E) Winter (F) static (G) solid (H) adjustable
Student:
H