Answer: The adjective in this sentence is describing "lemonade".
Step-by-step explanation: In the sentence diagram provided, the adjective "pink" is describing the noun "lemonade", which is working as a direct object. Moreover, "pink" is a qualifying adjective. In other words, "pink" is expressing an attribute of "lemonade" since it is stating which is its colour. Furthermore, the adjective is premodifying "lemonade" because it is preceding this noun.