一道高一英语填空题

问题描述:

一道高一英语填空题
-Really? I can't beliebe it!But are you______?
-You can trust me.I'm serious .
A.making faces b,holding up your hand
c,shaking your headd,pulling my leg
请说明为什么要选这个选项

Really?I can't beliebe it!But are you_pulling my leg __?
-You can trust me.I'm serious .
pull my leg是开玩笑的意思,一个俚语