(D) Glucose → Pyruvate →(Lack of oxygen) Lactic acid + Energy
In muscle cells, when oxygen is lacking, pyruvate is converted to lactic acid (not ethanol). Ethanol + CO₂ is produced in yeast, not muscles.
Source: Life Processes, Section 5.3 Respiration
The key distinction: anaerobic respiration in muscles produces lactic acid, while anaerobic respiration in yeast produces ethanol + CO₂. Options A and C describe yeast fermentation. Option B describes aerobic respiration. Examiners frequently test this difference, so always specify the organism/tissue when writing about anaerobic respiration.