You will be given a definition of a task first, then some input of the task.
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").

Fact1: staying warm has a positive impact on an animal 's survival, Fact2: With a thick fur coat and 4 inches of fat a bear stays warm., Question: What has a positive impact on an animal's survival? (A) four limbs (B) sensory neurons (C) low water availability (D) fur and fat (E) loss of food (F) heat energy (G) hormones (H) destruction of habitat
Output:
D