Detailed Instructions: 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: Population density is the average number of individuals per unit of area or volume., Fact2: Density is the population divided by the area., Question: What is the average number of individuals per unit of area or volume? (A) population divided by class (B) population divided by area (C) solid, liquid, gas (D) biological diversity (E) competing for resources (F) population divided by income (G) population divided by wealth (H) Something that makes plants green
A:
B