Answer
The charge stored on $C_1$ and $C_2$ together is more than the charge stored previously on $C_1$
Work Step by Step
When two capacitors are in parallel, the equivalent capacitance is the sum of the two capacitors.
Therefore, the equivalent capacitance is $~~C_{12} = C_1+C_2$
The equivalent capacitance $C_{12}$ is more than $C_1$
In general: $~~q = C V$
Since the equivalent capacitance is more than $C_1$ while $V$ remains the same, the charge stored on $C_1$ and $C_2$ together is more than the charge stored previously on $C_1$.
