**Core Concept**
Glucocorticoids and mineralocorticoids are two types of steroid hormones produced by the adrenal gland. While glucocorticoids primarily regulate glucose metabolism, protein catabolism, and anti-inflammatory responses, mineralocorticoids control electrolyte balance and blood pressure. Some glucocorticoids have mineralocorticoid activity, but not all.

**Why the Correct Answer is Right**
The correct answer is a glucocorticoid that does not have significant mineralocorticoid activity. This is because it lacks affinity for the mineralocorticoid receptor (MR), which is responsible for the salt-retaining effects of mineralocorticoids. The MR is often activated by aldosterone, a potent mineralocorticoid. Glucocorticoids like dexamethasone and betamethasone are synthetic steroids that have a lower affinity for the MR compared to the glucocorticoid receptor (GR).

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a glucocorticoid with significant mineralocorticoid activity, binding to the MR and affecting electrolyte balance.
**Option B:** This option is incorrect because it is a glucocorticoid with minimal mineralocorticoid activity, primarily affecting glucocorticoid receptors.
**Option C:** This option is incorrect because it is a glucocorticoid with moderate mineralocorticoid activity, influencing both glucocorticoid and mineralocorticoid receptors.

**Clinical Pearl / High-Yield Fact**
When choosing a glucocorticoid for replacement therapy in patients with adrenal insufficiency, it's essential to select a steroid with minimal mineralocorticoid activity to avoid excessive sodium retention and hypertension.

**Correct Answer: D.**