**Core Concept:** Charas/ganja refers to a concentrated form of cannabis, primarily obtained from the resin of the Cannabis Sativa plant. Cannabis contains various psychoactive compounds, such as tetrahydrocannabinol (THC), which is responsible for the psychoactive effects of the drug.

**Why the Correct Answer is Right:** Charas/ganja is made by collecting the resin from the female flowers of the Cannabis Sativa plant. The resin is then kneaded and formed into balls or pressed into cakes, which are the traditional forms of charas. The plant's psychoactive properties are due to the presence of tetrahydrocannabinol (THC), which binds to cannabinoid receptors in the brain and alters mood, perception, and cognition.

**Why Each Wrong Option is Incorrect:**

A. **False**: Charas is not obtained from the leaves or stems of the plant, only from the resinous parts.
B. **False**: Ganja is just a term for cannabis, not a method of preparation. Charas is the correct term for the prepared resin.
C. **True**: Charas is a traditional form of cannabis preparation in South Asia, but the correct answer is still Cannabis Sativa, not the resin extraction method.
D. **False**: Charas is not obtained from the seeds of the plant, but from the resinous parts.

**Clinical Pearl:** Charas is a potent form of cannabis with a high THC content, which can lead to serious side effects like dizziness, paranoia, and impaired coordination. Regular use can cause long-term cognitive and mood changes, and dependence.

**Correct Answer:** C. Cannabis Sativa - The correct answer refers to the plant species, not the preparation method. Charas is the traditional form of cannabis preparation in South Asia, prepared from the resinous parts of the plant.