Step 1: Understanding the sentence context.
The sentence requires the use of the past perfect tense, as it describes an action that happened before another action in the past (his friend went before he reached there). The past perfect tense is formed using "had" + past participle.
Step 2: Identifying the correct option.
- (A) goes is incorrect because it is in the present tense, which doesn't fit the context.
- (B) went is in the simple past tense, but the past perfect is needed for the correct sequence of actions.
- (C) had gone is correct because it uses the past perfect tense, indicating that the friend left before another past action occurred.
- (D) will be going is incorrect because it is in the future continuous tense.
Step 3: Conclusion.
Thus, the correct answer is (C) had gone.