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: Arthropods are the largest phylum of invertebrates., Fact2: Invertebrates are animals without a backbone., Question: what are arthropods the largest phylum of? (A) humans (B) absorb light energy (C) converting mass to energy (D) fish (E) animals without a backbone (F) remains of prehistoric life (G) h2o (H) Earth orbiting the Sun
A:
E