In this question, the phrase 'nos gusta la playa' completes the sentence about the family going to Hawaii.
The correct phrase to complete the sentence is 'D. nos gusta la playa.'.
In this case, 'nos gusta' is used to indicate that 'we like' the beach. The verb 'gustar' in Spanish functions differently compared to English, where the subject is the thing being liked, not the person doing the liking.
Therefore, 'nos gusta' translates to 'we like' in this context.