Which of the following phases of pharmacokinetics is described as the removal of the drug or its metabolites through the kidneys, gastrointestinal tract, skin, or lungs?

A. Distribution: This phase involves the transportation of the drug throughout the body after absorption, not removal. B. Metabolism: This phase involves the chemical alteration of the drug in the body, often in the liver, not its removal. C. Absorption: This phase involves the drug entering the bloodstream after administration. D. Excretion: This is the phase where the drug or its metabolites are removed from the body through various routes such as the kidneys, gastrointestinal tract, skin, or lungs.