Three capacitors,each of $3\,\mu F$,are provided. These cannot be combined to provide the resultant capacitance of.........$\mu F$

The equivalent capacitance between points $X$ and $Y$ in the given figure is . . . . . . . (in $\mu F$)

The potential difference across the $4 \mu F$ capacitor in series with the parallel combination in the following circuit is: (in $V$)

The combination of capacitors with $C_1 = 3\,\mu F$,$C_2 = 4\,\mu F$,and $C_3 = 2\,\mu F$ is charged by connecting $A$ and $B$ to a battery. Consider the following statements:
$I.$ Energy stored in $C_1$ $=$ Energy stored in $C_2$ $+$ Energy stored in $C_3$
$II.$ Charge on $C_1$ $=$ Charge on $C_2$ $+$ Charge on $C_3$
$III.$ Potential drop across $C_1$ $=$ Potential drop across $C_2$ $=$ Potential drop across $C_3$
Which of these is/are correct?

What is the potential difference between points $A$ and $B$ in the circuit shown (in $V$)?

What is the equivalent capacitance between $A$ and $B$ in the given figure (all values are in farad)?