A

The capacitance of a conductor is defined as the ability of the conductor to store electric charge per unit voltage, expressed mathematically as:
$$ C = \frac{Q}{V} $$
where $C$ is the capacitance, $Q$ is the charge stored, and $V$ is the voltage across the conductor.

From the formula, we can see that capacitance is directly related to the charge $Q$ and the voltage $V$. Additionally, the capacitance depends on the physical dimensions and nature of the material used for the conductor (such as dielectric properties). Hence, both charge and voltage affect capacitance.

Therefore, among the options given:
- Option A (Charge) affects capacitance.
- Option B (Voltage) also affects capacitance.
- Option C (Nature of the material) affects capacitance since different materials have different dielectric constants.

Hence, capacitance does not depend on a standalone charge or voltage but is defined by their relationship. The correct answer is:
Option A: Charge, as capacitance does indeed depend on the charge stored but is not solely defined by it.