Well behaviors are completely "involuntary" and reflect people's true states. Most people will only attempt to control their nonverbal behavior when they are lying.
I think b is punctuated correctly hope this helps.
Humor is subjective, so for some people a statement like that could be considered as such. Going by that, if we are looking at this statement as a joke then it would be classified as humor with some racist undertones, but it really depends on the context. That aside, I would say it’s racist because it can be used to generalize Asians in a hurtful way.
