**Core Concept**
The question is testing the understanding of the pharmacological management of Marfan syndrome, specifically the use of beta-blockers to delay the progression of aortic dilatation.

**Why the Correct Answer is Right**
The drug used to delay the progression of aortic dilatation in Marfan syndrome is beta-blockers, particularly atenolol. Beta-blockers work by reducing the heart rate and contractility, thereby reducing the shear stress on the aortic wall. This is achieved by blocking the action of beta-1 adrenergic receptors in the heart, which are responsible for increasing heart rate and contractility. The use of beta-blockers has been shown to reduce the risk of aortic dissection and rupture in patients with Marfan syndrome.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because ACE inhibitors, while useful in managing hypertension in Marfan syndrome, do not have a specific effect on aortic dilatation.
* **Option B:** This option is incorrect because calcium channel blockers, while useful in managing hypertension, do not have a specific effect on aortic dilatation.
* **Option D:** This option is incorrect because statins, while useful in managing atherosclerosis, do not have a specific effect on aortic dilatation in Marfan syndrome.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that beta-blockers should be started early in the management of Marfan syndrome, ideally before the aorta has dilated significantly. This can help prevent the progression of aortic dilatation and reduce the risk of aortic dissection and rupture.

**Correct Answer:** C. Atenolol