a$)$ C integer literals are formed in the following way:

Octal literals consist of a leading $0$ followed by zero or more octal digits $(0$ through $7)$

Hexadecimal literals consist of a leading $0$ followed by $x$ or $x$ followed by one or more hexadecimal digits $(0$ through $9,$ a through $f,$ or A through $F)$

Decimal literals consist of one non$-$zero decimal digit $(1$ through $9)$ followed by zero or more decimal digits $(0$ through $9).$

Construct a regular expression for the $C$ integer literals.

$[8$ Marks$]$