Three capacitors $1, 2$ and $4\,\mu F$ are connected in series to a $10\, volts$ source. The charge on the plates of middle capacitor is

  • A

    $7\,\mu C$

  • B

    $\frac{{40}}{7}\,\mu C$

  • C

    $\frac{{20}}{7}\,\mu C$

  • D

    $\frac{{1}}{7}\,\mu C$

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