补全对话

（D=Darren, C= Carol）

D: Hi, Caro!  ____ 

C: Oh, hi, Darren. I'm just getting ready for the Red Nose Day concert tomorrow.

D: Oh really? Well, I'm free this afternoon.  ____ 

C:Actually, I've nearly finished. Jim and I are going to put up some ads later, though. Could you please help us with that?

D:   ____ 

C: That's wonderful! Oh, there's one more thing. Would you mind coming early tomorrow to help sell tickets at the door?

D: Not at all,  ____ 

C: Around six would be great.

D: OK. ____ 

C: Great. Thanks, Darren.

A.No problem.

B.See you then.

C.Of course not.

D.What are you doing?

E.Can I give you a hand?

F.What time shall I be there?

G.Have you finished your homework?

已知函数$f\left(x\right)=\left\{\begin{array}{c}{\log }_{4}x,x>0\\ 3^x,x\le 0\end{array}\right.$,则$ff\left(\frac{1}{16}\right)$=（　　）