$(17$ pt$)$ Face$-$centered cubic $($FCC$)$ is a Bravais lattice. Define the primitive vector, $a_1,a_2,$ and $a_3,$ using the $x,y,$ and $z$ axes shown to the right. Use the bottom left corner of the unit cell as the origin, $O.$ The conventional FCC unit cell has $14$ atoms. Define the position of each atom in terms of the primitive unit vectors, e$.$g$.,$ the origin is $P_0=0*a_1+0*a_2+0*a_3.$