**Core Concept**
Magnesium and aluminum salts are commonly used in antacid preparations to neutralize gastric acid and provide quick relief from heartburn and indigestion. The combination of these salts offers several advantages over single-component preparations.

**Why the Correct Answer is Right**
The combination of magnesium and aluminum salts is superior because magnesium has a rapid onset of action, but its effects are short-lived due to its high solubility in water. Aluminum, on the other hand, has a slower onset of action but provides longer-lasting relief. When used together, magnesium helps to rapidly neutralize gastric acid, while aluminum maintains the pH balance for a longer duration. This synergistic effect makes antacid combinations more effective than single-component preparations.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the mechanism by which magnesium and aluminum salts work together.
* **Option B:** This option is incorrect because it implies that the combination of magnesium and aluminum salts is only useful for rapid relief, ignoring their synergistic effects.
* **Option C:** This option is incorrect because it suggests that the combination of magnesium and aluminum salts is only useful for treating peptic ulcers, which is not the primary indication for antacids.

**Clinical Pearl / High-Yield Fact**
When prescribing antacids, it's essential to consider the patient's renal function, as aluminum can accumulate in the body and cause toxicity in patients with impaired renal function.

**Correct Answer: C. The combination of magnesium and aluminium salts provides a rapid onset of action and long-lasting relief from heartburn and indigestion.**