Also consider the following $1-$bit ALU that performs AND, OR$,$ and addition on a and $b.$

Note that one can select between three values using the Operation select line to the Result multiplexor. Assume that the Ainvert and Binvert signals can be asserted or de$-$asserted and that the Carryln signal can be de$-$asserted or taken from the CarryOut of the preceding $1-$bit ALU. The value of a NOR $b$ can be obtained by asserting Ainvert and Binvert and selecting an AND operation.

$($a$)$ Describe how the value of a NOR $b$ can be obtained. $(6$ points$)$

$($b$)$ Describe how the value of a NAND $b$ can be obtained. $(6$ points$)$

$($c$)$ Describe how the value of a XOR $b$ can be obtained. $(4$ points$)$