If you were surprised with a tough question during job interview, what would your ideal silent body language be?

Take breathing deeply then smiling that's mean change the question please. 

Thanks

As for me (3) " Smiling " will be a proper action against this question.

Keeping eye contact while smiling

2. Keeping Eye Contact.

3. Smiling.

I would Smile and keep eye contact also.

I'd give an eye contact and smile to show him that I'm not losing my confidence. 

smiling and be honest, not to hesitate to say the truth I do not know instead of pretending 

I will 

2. Keeping Eye Contact.

3. Smiling 

That will give them an impression about my personality as self confidence person 

Smile and keep eye contact while trying to think about an appropriate answer to the questions. 

 in fact  ، I think  I will be surprise Being too erect or rigid

I would give a big smile ....... :)