**Core Concept**
During an acute attack of asthma in labor, the primary concern is to ensure the safe delivery of both the mother and the baby while rapidly reversing bronchospasm. This requires choosing a medication that effectively relieves bronchospasm, is safe for both the mother and the fetus, and does not compromise uteroplacental blood flow.

**Why the Correct Answer is Right**
The preferred drug for acute asthma attacks during labor is salbutamol (also known as albuterol in the US), a short-acting beta-2 agonist (SABA). Salbutamol acts by stimulating beta-2 receptors in the smooth muscle of the bronchi, causing bronchodilation and relieving bronchospasm. It has a rapid onset of action, making it ideal for acute asthma attacks. Moreover, salbutamol is considered safe for both the mother and the fetus, as it does not cross the placenta in significant amounts.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
Salbutamol is the preferred drug for acute asthma attacks during labor due to its rapid onset of action, safety for both the mother and the fetus, and effectiveness in relieving bronchospasm.

**Correct Answer: A. Salbutamol**