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: Viruses are not cells., Fact2: Plant cells are surrounded by a cell membrane and a cell wall., Question: What lacks walls and membranes? (A) deserts (B) flower cells (C) viruses (D) fungi (E) tree cells (F) bacteria (G) plant cells (H) alpacas
A:
C