In each part below, draw an NFA $($statemachine$)$ accepting the indicated language over $\{$a$,$ b$\}.$

a$)$ The language of all strings containing no more than one occurrence of the string aa$.($The string aaa contains two occurrences of aa$.)$

b$)$ The language of all strings containing both bb and aba as substrings.

c$)$ The language of all strings containing both aba and bab as substrings.