a$.$ Explain how recursion is used to calculate factorials, and provide a C program

that implements this approach.

b$.$ Generate the intermediate code produced by the factorial program, and

represent the Three$-$Address Code $($TAC$)$ in various forms.

c$.$ Design the activation record for each recursive call in the factorial function,

particularly for factorial$(4),$ and explain the components and structure of these

records.

d$.$ Generate the intermediate code for the program described in question $($b$),$

ensuring to accurately represent its logic and structure.