You will be given a definition of a task first, then some input of the task.
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: Prokaryotes are single-celled organisms that lack a nucleus., Fact2: Prokaryotes are usually microscopic and bacteria is an example of a prokaryote., Question: What do some bacteria lack? (A) Energy (B) nucleus (C) glucose (D) Energy. (E) properties (F) oxygen (G) alleles (H) warmth
Output:
B