Instructions: 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").
Input: Fact1: Genes that are located on the same chromosome are called linked genes., Fact2: Thousands of genes are linked together in a chain to form chromosomes., Question: What do genes do to form a chain? (A) interact (B) spread flower seeds (C) Break apart (D) Link together (E) reproduce (F) Duplicate (G) Break down (H) It expands
Output:
D