What is the language generated by the context$-$free grammar

S$->>$aSbbb$|$Sbbb$|$aS$|$e

Here S is the start variable and a$,$ b are terminals.

A$.\{$a$^$i b$^$k$|0<=3$i$<=$ k$\}$

B$.\{$a$^$i b$^$k $|0<=$k$<=3$i$\}$

C$.\{$a$^$i b$^3$k$|$i$>=0,$ k$>=0\}$

D$.\{$a$^$i b$^3$k l$0<=$i$<=$ k$\}$

E$.\{$a$^$i b$^3$k $|0<=$k$<=$i$\}$

F$.$ None of the above.