Detailed 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").
Q: Fact1: Adult sponges produce eggs and sperm., Fact2: An adult is mature, fully developed., Question: What produces both eggs and sperm? (A) Plant reproduction (B) sub-units of species (C) gastropod shells (D) an individual mature sponge (E) Microscopic organisms (F) members of their own species (G) peachleaf willow (H) seed dispersal
A:
D