**Core Concept**
The question tests the understanding of **angiotensin-converting enzyme (ACE) inhibitors**, a class of medications used to treat hypertension and heart failure. ACE inhibitors work by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor.

**Why the Correct Answer is Right**
The correct answer is an ACE inhibitor that is active in its administered form, meaning it does not require metabolic conversion to exert its effect. Most ACE inhibitors are prodrugs, which are inactive until they are metabolized in the body.

**Why Each Wrong Option is Incorrect**
**Option A:** Is a prodrug, requiring conversion to its active form.
**Option B:** Also a prodrug, needing hepatic conversion to become active.
**Option D:** Is another prodrug, which is converted to its active metabolite.

**Clinical Pearl / High-Yield Fact**
It's crucial to recognize that **lisinopril** is an exception among ACE inhibitors as it is not a prodrug, making it a notable example for medical students.

**Correct Answer:** D. Lisinopril