**Core Concept**
Saturated salt solutions are used to determine the density of substances. Objects with densities greater than that of the solution will sink, while those with densities less than the solution will float. The concept being tested here involves the specific densities of various substances relative to a saturated salt solution.

**Why the Correct Answer is Right**
The correct answer involves identifying a substance that does not float in a saturated salt solution. This requires knowledge of the densities of different substances. A saturated salt solution typically has a density around 1.2 g/cm³. Substances with densities greater than this value will sink, while those with densities less than this value will float. The correct answer is a substance with a density greater than that of the saturated salt solution.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it is a substance that typically floats in a saturated salt solution, having a density less than that of the solution.
* **Option B:** This option is incorrect because it is a substance with a density that is close to that of the saturated salt solution, but not significantly greater.
* **Option D:** This option is incorrect because it is a substance that typically floats in a saturated salt solution, having a density less than that of the solution.

**Clinical Pearl / High-Yield Fact**
Remember that the density of a substance plays a crucial role in determining whether it will float or sink in a solution. This concept is essential in various medical and laboratory settings.

**Correct Answer: C. Lead**