q$\mathrm{.}6)$ using $4$ variable Kmap, simplify the function

a$)x{z}^{\text{'}}+x{w}^{\text{'}}$

c$)y{w}^{\text{'}}+x^{\text{'}}{z}^{\text{'}}w+xyz$

b$)xz+x{w}^3$

d$)$ none of the above.