请根据对话内容，从方框内的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
A: What do you like doing?
B: Singing.       
A: You can't be a famous pop star unless you're really good.      
B: Yes, I always play my guitar when I listen to pop music on the radio.     
A: Great! Have you been in any pop star competitions in your school?
B:        I didn't win the prize.
A: That's too bad!
B: But it doesn't matter. I'll keep working hard.   

A．Yes．but only once．            B．I want to be a pop star． C．I want to be a movie star．        D．Can you play the guitar? E．Some day I'm going to make it． F．I'm going to buy an electric guitar when I have enough money． G．What are you going to buy when you have enough money?