A

Step 1: Analyze the circuit. Capacitors C1, C2, and C3 are connected in a configuration where C1 is in series with a parallel combination of C2 and C3.
Step 2: Statement (I): Energy stored in C1 is given by \( U_1 = \frac{1}{2} C_1 V_1^2 \), and the total energy is \( U = U_1 + U_2 + U_3 \) where U2 and U3 are the energies stored in C2 and C3 respectively. This is true as per energy conservation laws.
Step 3: Statement (II): In the series arrangement of capacitors, the charge (Q) on every capacitor remains the same. Thus, \( Q_{C1} = Q_{C2} + Q_{C3} \) also holds true since the total charge divides across parallel paths. Therefore, statement II is also correct.
Step 4: Statement (III): This statement is incorrect as the potential drop across capacitors in series is not equal; for capacitors in parallel, they have the same potential difference.
Thus, the correct options are I and II.
Therefore, the correct answer is A.