How would you best describe someone who is "perplexed"?

Describing someone as "perplexed" indicates that they are confused or bewildered. This term reflects a state of mental uncertainty where an individual is struggling to understand something that may be complex or difficult to grasp. The feeling of perplexity often arises in situations where information is ambiguous or when faced with challenges that do not have clear solutions.

In contrast, the other descriptions do not align with the meaning of "perplexed." Feeling excited and happy conveys positive emotions, while relaxed and calm suggests a state of ease, both of which do not match the notion of being confused. Being very friendly focuses on a person's social demeanor, which is unrelated to the state of one's comprehension or understanding. Hence, the correct choice encapsulates the essence of feeling puzzled and unsure.