Final answer:
Docusate sodium's therapeutic effect comes from its ability to soften the feces by increasing water and fats in the stool, acting as a stool softener. Therefore , the correct answer options is d)
Step-by-step explanation:
The therapeutic effect of docusate sodium is primarily due to its action as a stool softener. Its mechanism involves softening the feces by increasing the amount of water and fats within the stool.
This helps to soften and blend stool contents, making it easier to pass through the colon. Docusate sodium achieves this by acting as a surfactant, which lowers the surface tension and allows water and fats to penetrate the stool. Therefore, it does not work by lubricating the feces, creating an osmotic effect, or directly stimulating motor activity in the gut.