A processor unit $($PU$)$ is an un$-$characterized processor in a mainframe. Which characterized processor executes commands?

Question $29$Select one:

a$.$

zAAP $($z Application assist processor$)$

b$.$

CP $($Central processor$)$

c$.$

zIIP $($Integrated information processor$)$

d$.$

SAP $($System assistance processor$)$