What is the minimum box volume requirement for two $12$ AWG conductors that pass unbroken through a lighting outlet box, two $14$ AWG conductors enter the box and splice to two $14$ AWG conductors leaving the box, and two $16$ AWG fixture wires that supply a luminaire?

a$.12\mathrm{.}5i{n}^3$

b$.14$ in$.{?}^3$

c$.16$ in$.{?}^3$

d$.18i{n}^3$

e$.20\mathrm{.}5$ in$.{?}^3$