His sister is outgoing.(对划线部分提问)

问题描述:

His sister is outgoing.(对划线部分提问)

划线部分是什么呢?您没有标出来!
如果划线部分是His:Whose sister is outgoing?
如果划线部分是His sister:Who is outgoing?
如果划线部分是outgoing:What is his sister like?
注:outgoing adj.外向的,乐于交友的
(说明:I am just a middle school student.
能力有限,答案仅供参考.如有不对之处,欢迎指正!