A. cytosol
B. Mitochondria
C. Matrix
D. Endoplasmic reticulum

Glycolysis is the metabolic pathway that breaks down glucose into pyruvate, releasing energy and producing ATP. This process occurs in the cytoplasm of the cell.

Therefore, the correct answer is:

A. cytosol

The correct answer to the question: "Glycolysis process occur in?" is "cytosol".