In this task, you need to answer basic science questions. For each question, several terms are intentionally masked with ***. This masking can cover very few or many of the question words. Clearly, if masked terms are important, the modified question will be impossible to answer. Please indicate the correct answer with one of the following responses: "A", "B", "C", "D" or "E". While "A"-"D" correspond to the answer options provided in the input, "E" represents "I don't know" for questions that do not provide enough information. Respond via "E" if the question is not answerable. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'.

Question: Which *** help to destroy pathogens such as bacteria that enter the human body?  (A) red blood cells (B) liver cells (C) white blood cells (D) brain cell.
C.

Question: An *** that can *** the *** of an ***, such as its speed or direction, is called ___.  (A) solubility (B) buoyancy (C) force (D) potential energ.
D.

Question: *** *** *** *** *** change water *** *** liquid *** *** solid?  (A) decrease the temperature (B) increase the temperature (C) decrease the mass (D) increase the mas.

A.