## **Core Concept**
The question tests the understanding of parasitic eggs and their behavior in different solutions, specifically focusing on the effect of salt solution on the visibility of eggs under microscopy. This requires knowledge of parasitology, particularly the characteristics of eggs from different parasites.

## **Why the Correct Answer is Right**
The correct answer, **D. Taenia**, involves understanding that eggs of certain parasites can dissolve or become invisible in a saturated salt solution due to their specific composition. Taenia eggs, when subjected to a saturated salt solution, tend to disintegrate or become less visible, which aligns with the given scenario.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because the eggs of some parasites are indeed visible in salt solutions and do not necessarily disappear from view.
- **Option B:** This option does not match the description provided, as the behavior of these eggs in salt solution does not align with becoming invisible.
- **Option C:** Similarly, this option does not fit the scenario described, as the eggs' behavior in a saturated salt solution does not match the given condition.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the visibility of parasitic eggs can change based on the solution they are suspended in. For example, a saturated salt solution can cause some eggs to float or become less visible, which is a principle used in certain parasitological diagnostic techniques.

## **Correct Answer:** .