**Core Concept**
The question tests the student's knowledge of the pharmacological effects of certain drugs on uterine contractility and their potential to cause pulmonary edema. The correct answer involves a drug that has both tocolytic and fluid-retaining properties.

**Why the Correct Answer is Right**
The correct answer is a drug that inhibits uterine contractility by blocking calcium influx into smooth muscle cells, thereby preventing premature labor. However, this drug also has a side effect of causing fluid retention, which can lead to pulmonary edema due to the increased hydrostatic pressure in the pulmonary capillaries. This is a classic example of a drug that has a beneficial effect on one condition (tocolysis) but a detrimental effect on another (fluid retention).

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not have a significant effect on uterine contractility or fluid retention. Drugs like magnesium sulfate have a tocolytic effect but do not cause fluid retention.
* **Option B:** This option is incorrect because it does not have a significant effect on uterine contractility but causes fluid retention. Drugs like spironolactone have a diuretic effect and would not cause pulmonary edema.
* **Option C:** This option is incorrect because it has a tocolytic effect but is not associated with fluid retention. Drugs like ritodrine have a beta-2 agonist effect, which inhibits uterine contractility but does not cause fluid retention.

**Clinical Pearl / High-Yield Fact**
The drug that inhibits uterine contractility and causes pulmonary edema is often used in the management of preterm labor but requires careful monitoring of fluid status to prevent complications.

**Correct Answer: C. Terbutaline**