D. Examine her own perception and then check in with Ivan about his behavior
The question asks about what Tamara should to do better interpret the situation and communicate appropriately. In order for her to better interpret the situation she needs to examine her own perception. Why does she feel that Ivan is unusually quiet? Does she truly think that it is directed towards her? Then she should check in with him. Telling him that he's being inconsiderate as option A suggests is not helpful. Option B also does not solve the problem either. And if Ivan is going through something, offering him help or support may be what he needs. Option C is also not correct because Tamara should not be providing therapy and she doesn't even know what is going on.
Overthinking is most likely a big problem in this case, because in case of talk with the 'upset' person, we tend to imagine what should be the reason.
In this case, Tamara should examine her own perception, she probably is overthinking about it, after that thoughts examination and having a more objective perspective, she should examine closely Ivan's behaviour.
A semicolon can be used to combine two closely related independent clauses if they are not already joined by a coordinating conjunction (and, but, or, nor, for, so, or yet).
