选择恰当的选项补全下面的对话。

A．on   B．cap   C．under   D．bag   E．in

A：Hi，Mum．Where is my?

B：Is itthe desk?

A：No, it isn't．

B：Is ityour?

A：No, it isn't．

B：Look! It'syour head!

A：Oh! Silly me!