Answer
Glycolysis occurs in the cytoplasm
Explanation :
Aerobic respiration occurs in mitochondria, whereas anaerobic respiration occurs in the cytoplasm.
Glycolysis is common to both aerobic and anaerobic respiration.
Glucose is (C6H12O6) converted into 2 molecules of pyruvic acid ( CH3COCOOH)
In aerobic respiration, pyruvic acid is converted into acetyl coenzyme A that enters Citric acid cycle in mitochondrion.
In anaerobic respiration, pyruvic acid is converted either into lactic acid or ethyl alcohol (C2H5OH) and $CO_2$ in cytoplasm.