**Core Concept**
Glucocorticoids and mineralocorticoids are two types of steroid hormones produced by the adrenal cortex. While glucocorticoids primarily regulate glucose, protein, and fat metabolism, mineralocorticoids control electrolyte balance by acting on the kidneys to reabsorb sodium and excrete potassium. The distinction between these two activities is crucial in the design of glucocorticoid preparations with minimal mineralocorticoid effects.

**Why the Correct Answer is Right**
The correct answer is a glucocorticoid that lacks significant mineralocorticoid activity. This is achieved through modifications to the steroid molecule, such as the addition of a methyl group at the 6-alpha position, which blocks the glucocorticoid receptor's interaction with the mineralocorticoid receptor. This results in a glucocorticoid with potent anti-inflammatory and immunosuppressive effects but negligible mineralocorticoid activity.

**Why Each Wrong Option is Incorrect**
**Option A:** This glucocorticoid has a significant mineralocorticoid effect, which is undesirable in many clinical situations.
**Option B:** This glucocorticoid has a moderate mineralocorticoid effect, making it less ideal than the correct answer.
**Option C:** This glucocorticoid lacks both glucocorticoid and mineralocorticoid activity, making it unsuitable for therapeutic use.

**Clinical Pearl / High-Yield Fact**
When selecting a glucocorticoid for treatment, it is essential to consider the potential for mineralocorticoid activity, which can lead to electrolyte imbalances and hypertension.

**Correct Answer:** C. Hydrocortisone