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: Some viruses have an envelope of phospholipids and proteins., Fact2: Viruses are enveloped by similar membranes., Question: What have similar membranes? (A) PDAs (B) humans (C) viruses (D) crocodiles (E) animals (F) sharks (G) fur seals (H) insects
A:
C