Two air capacitors $A=1 \mu F, B=4 \mu F$ are connected in series with $35 \mathrm{~V}$ source. When a medium of dielectric constant $\mathrm{K}=3$ is introduced between the plates of $\mathrm{A}$, change on the capacitor changes by
(A) $16 \mu \mathrm{c}$
(B) $32 \mu \mathrm{c}$
(C) $28 \mu \mathrm{c}$
(D) $60 \mu \mathrm{c}$