Five identical capacitor plates are arranged such that they make four capacitors each of $2\mu F$. The plates are connected to a source of voltage 10 V. The total charge on plate C is:

As alternative plates are connected to the left and right side of the battery, four capacitors are connected in parallel combination and charge across each is

q = CV

Two surfaces of plate C marks two capacitors, one with B and other with D and C  is connected to positive terminal of the battery so total charge on plate C is given as

${\mathrm{q}}_{\mathrm{C}}=2\mathrm{CV}=+40\mathrm{\mu C}$