## Core Concept
The question tests knowledge of antimalarial drugs and their side effect profiles, specifically focusing on neuropsychiatric adverse reactions. Antimalarial drugs are crucial in the management and prevention of malaria, but they can have various side effects. Neuropsychiatric adverse reactions include symptoms like hallucinations, psychosis, and depression.

## Why the Correct Answer is Right
Mefloquine is the correct answer because it is well-documented to cause neuropsychiatric adverse reactions. These can range from anxiety, depression, and hallucinations to more severe psychiatric disturbances like psychosis. The mechanism behind these effects is not entirely clear, but it is thought to be related to its action on the central nervous system. Mefloquine's use has been associated with a higher risk of neuropsychiatric side effects compared to some other antimalarial drugs.

## Why Each Wrong Option is Incorrect
- **Option A:** While certain antimalarial drugs have side effects, without specifying the drug, it's hard to directly refute this option based on the information given. However, we know that not all antimalarial drugs are equally associated with neuropsychiatric effects.
- **Option B:** Similarly, this option lacks specificity, making it difficult to assess its accuracy directly.
- **Option C:** This option is a distractor and does not correspond with the well-known side effect profiles of commonly used antimalarial drugs in relation to neuropsychiatric reactions.

## Clinical Pearl / High-Yield Fact
A key point to remember is that Mefloquine is associated with neuropsychiatric side effects, and its use should be carefully considered, especially in individuals with a history of psychiatric disorders. The risk-benefit analysis must be weighed for each patient, and alternatives should be considered when possible.

## Correct Answer Line
**Correct Answer: D. Mefloquine.**