Pyruvate Can Be Converted to Lactate Instead of Going to the Preparatory

Multiple Choice

Pyruvate can be converted to lactate instead of going to the preparatory reaction. Why does this occur?

A) The cells need lactate to produce ATP.
B) There is no sunlight.
C) The cells doing the reaction are prokaryotes.
D) Oxygen is not available.
E) There is a shortage of glucose.