Correct Answer.

The proof
1 p q r premise
2 p assumption
3 q r e 1, 2
4 q e1 3
5 p q i 2-4

is correct. Notice its global strategy. After stating the premise in line 1, we seek to show the implication p q. To show this, we open a box, assume p in line 2 and attempt to show q, whereafter we immediately close that box, citing -introduction.
Back to Question.
Next Question.