**Core Concept**
Anaesthesia in infants requires careful consideration of their unique physiology and pharmacology. Infants have a large surface area to body mass ratio, which affects drug absorption and distribution. They also have a developing liver and kidneys that can impact drug metabolism and excretion.

**Why the Correct Answer is Right**
The correct answer is **C. Inhalational agents**. Inhalational agents, such as sevoflurane or halothane, are commonly used for anaesthesia in infants due to their rapid onset and offset of action. They are also less likely to cause histamine release and subsequent hypotension, which can be problematic in this age group. The use of inhalational agents allows for precise control of the depth of anaesthesia and is often preferred in pediatric anaesthesia.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a relevant answer, as topical anaesthetics are not typically used for general anaesthesia in infants.
**Option B:** Not a correct answer, as intravenous agents can be used in infants but are not the preferred choice for general anaesthesia.
**Option D:** Not a correct answer, as regional anaesthesia is not commonly used for general anaesthesia in infants.

**Clinical Pearl / High-Yield Fact**
Infants are more sensitive to the effects of anaesthetic agents due to their developing nervous system, making careful titration and monitoring crucial to avoid adverse effects.

**Correct Answer: C. Inhalational agents.**