Anaerobic metabolism can produce ATP up to 2.5 times faster than aerobic metabol

Anaerobic metabolism can produce ATP up to 2.5 times faster than aerobic metabolism. However, this comes with two disadvantages. One is that anaerobic metabolism can contribute to a state of metabolic acidosis. What is the primary mechanism by which anaerobic metabolism does this?

A) through the production of CO2 and its conversion to carbonic acid
B) through the conversion of lipid molecules to free fatty acids
C) through the production of ketones (keto acids) to make up for the deficiency in ATP production
D) through the conversion of pyruvate to lactate