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").

Fact1: Insulin helps cells take up glucose from the blood., Fact2: Blood Glucose Blood Glucose Glucose is the principal source of energy for mammalian cells., Question: Cells obtain energy from the blood with the help of (A) sweating (B) batteries (C) pancreas (D) electron (E) insulin (F) alveoli (G) oxygen (H) sunlight
E