Oil flowing at a rate of $180$ kg$/$min enters a parallel double pipe heat exchanger at $25$oC and is heated by a water stream flowing at rate of $300$ kg$/$min and entering to the heat exchanger at $80$oC$.$ Calculate oil exit temperature. Take CP$,$oil $=2$ kJ$/$kgK$,$ CP$,$water $=4\mathrm{.}2$ kJ$/$kgK$,$ U $=400$ W$/$m$2$K and A $=10$m$2.$

A$)49\mathrm{.}6$

B$)44\mathrm{.}6$

C$)39\mathrm{.}6$

D$)34\mathrm{.}6$

E$)29\mathrm{.}6$