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: Cells vary in size as well as shape, but all cells are very small., Fact2: Microscopes are needed as most aquatic invertebrates are quite small., Question: What can be used to see cells? (A) microscopes (B) A computer (C) mirrors (D) cell walls (E) barometers (F) binoculars (G) scattered light (H) flashlights
A:
A