The correct answer is: D) Cordial
Based on the sentence, Patty and Lilly were a little distant from the people taht assisted to the party. By the use of "even though" it is infered that they managed to be polite and friendly, matching with the definition of "cordial".
The word alienating implies isolation, which doesn't make a lot of sense in the sentence.
"Compliant" refers to obeying someone in a submissive way, we can inffer that Patty and Lilly were in the party by their own will and were not forced to do anything.
"Inherent" refers to existing in something as a permantent which doesn't make any sense either.
