In lactic acid fermentation, the final electron acceptor is:

The correct option is Pyruvate.

In cellular respiration, cells break down glucose to generate energy in the form of ATP. Under anaerobic conditions (where oxygen is absent), cells rely on fermentation to continue generating energy.

Lactic acid fermentation consists of two main steps:
1. Glycolysis: Glucose is converted into two molecules of pyruvate, producing a net gain of 2 ATP and converting 2 NAD⁺ into 2 NADH.
2. Lactate dehydrogenase reaction: To keep glycolysis running, the cell must regenerate the NAD⁺ pool. Pyruvate acts as the final electron acceptor, receiving electrons directly from NADH. This reduction reaction converts pyruvate into lactic acid (lactate) and regenerates NAD⁺.

Since pyruvate accepts the electrons from NADH, it serves as the final electron acceptor in this pathway.