Answer: D. The capacitor can store more charge at a given potential difference.
Step-by-step explanation:
The capacitance of a capacitor is given by:

Where, k is the dielectric constant.
When a dielectric is replaced with another having larger dielectric constant, the value of the capacitance increases.
The charge stored by the capacitor is given by:
Q = C V
where V is the voltage.
Thus, with increase in value of capacitance, the charge stored by the capacitor increases at a given potential difference.