An ‘adjunct’ in grammar is a word or phrase used to amplify the meaning of another word or words in a sentence. An adjunct can also be used as a way to add to something as a supplementary rather than an essential part. Given this knowledge, the best ANSWER: would be “in his car.” By using context, we already know ‘he’ is drinking tea, but it is supplementary to know the setting that his tea drinking took place.