$f(a)=3a-2=b-2$ $\implies$ $b=3a$ $f(b)=3b-2=2b+a$ $\implies$ $a=b-2$ Então: $a=3a-2$ $\implies$ $2a=2$ $\implies$ $a=1$ $f(a)=f(1)=3\cdot 1 -2=1$ $\implies$ $f(a)=1$ Portanto: $f(f(a))=f(1)=1$

Brasil!

$f(x) = 3x - 2$ $\therefore$ $f(a) = 3a - 2 = b - 2 \implies 3a = b$ e $f(b) = 3b - 2 = 2b + a \implies b = a + 2$ $\therefore$ $3a = b =3a =a+2 \implies 2a = 2 \implies \boxed{a = 1}$ $\therefore$ $f(a) = f(1) = 3(1) - 2 = f(1) = 1$ $\therefore$ $\boxed{f(f(a))= f(f(1)) = f(1) = 1} $ $\textbf{Resposta : Alternativa B}$