Four identical plates `1,2,3` and `4` are placed parallel to each other at equal distance as shown in the figure. Plates `1` and `4` are joined together and the space between `2` and `3` is filled with a dielectric of dielectric constant `k =2`. The capacitance of the system between `1` and `3` and `2 &4` are `C_(1)` and `C_(2)` respectively. The ratio `(C_(1))/(C_(2))` is-
A. `(5)/(3)`
B. `1`
C. `(3)/(5)`
D. `(5)/(7)`