You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.
Q: A student used the dimmest setting on a light microscope to observe a euglena and an amoeba. The student shined a narrow beam of light at the top of the cover slip. She observed that the euglena swam up toward the light but the amoeba did not. She knew the amoeba was alive because it slowly changed shape while she watched. What inference should the student draw from her observation?
(A) An amoeba can only move side to side. (B) An amoeba is unable to respond to light. (C) An amoeba moves too slowly to observe. (D) An amoeba only moves when it is hungry.
A:
B