**Core Concept**
The question requires knowledge of the pharmacological management of medical termination of pregnancy (MTP) in a patient with asthma. MTP involves the use of medications to induce uterine contractions and expel the contents of the uterus.

**Why the Correct Answer is Right**
In a patient with asthma, a beta-2 agonist can exacerbate bronchospasm. Therefore, a prostaglandin E2 (PGE2) analogue, such as misoprostol, is preferred over oxytocin or mifepristone, which can cause bronchoconstriction. Misoprostol acts on the uterus to induce contractions and is less likely to exacerbate asthma.

**Why Each Wrong Option is Incorrect**
**Option A:** Oxytocin is a potent uterotonic agent but can cause bronchoconstriction in patients with asthma. It is not the preferred choice in this scenario.
**Option B:** Mifepristone is an antiprogestin that can induce uterine contractions but can also cause bronchoconstriction and is not the preferred choice in a patient with asthma.
**Option C:** Methotrexate is an antifolate medication used for medical termination of pregnancy but is not the preferred choice for inducing uterine contractions.

**Clinical Pearl / High-Yield Fact**
When managing a patient with asthma for medical termination of pregnancy, consider using a PGE2 analogue like misoprostol to minimize the risk of exacerbating bronchospasm.

**Correct Answer: D. Misoprostol**