The correctly punctuated sentence is: d. the red-faced exhausted students are glad that gym is over.
In this sentence, "red-faced" is hyphenated correctly, while the other options lack necessary punctuation (such as commas) to separate the adjectives. Here are the corrected versions of the other sentences for clarity:
a. After gym class, the students appear tired, worn out, and thirsty.
b. The eager, energetic students are ready for gym to begin.
c. Before gym class, the students seem happy, excited, and ready to play.