一个寻宝游戏的寻宝通道如图1所示，四边形ABCD为矩形，且AB＞AD＞$\frac{1}{2}$AB，为记录寻宝者的行进路线，在AB的中点M处放置了一台定位仪器，设寻宝者行进的时间为x，寻宝者与定位仪器之间的距离为y，若寻宝者匀速行进，且表示y与x的函数关系的图象大致如图2所示，则寻宝者的行进路线可能为（　　）

根据对话内容, 从方框内选出能填入空白处的最佳选项。

A: Hello! May I speak to Jane, please?

B: ____ She is out at the moment.

A: Is that Mr. Smith?

B: Yes. ____

A: This is Tom. Jane invited me to the concert tomorrow. I'd like to come, but I can't.

B: ____ 

A: My mother is ill.

B: ____ Don't worry. I think she'll be all right soon.

A: I hope so. ____

B: No problem. I'll leave her the message.

A: Thanks a lot. Bye!

熊咆龙吟殷岩泉，____《新城道中》