Report writing describes events that have already taken place. Therefore, the narration is written in the past form.
Step 1: Understand the purpose of report writing.
A report provides factual information about an event that has already happened. Since it is a description of a completed event, it must be written in the past tense.
Step 2: Analyze the options.
(A) Present tense: This is used for general facts, not for reporting completed events.
(B) Simple future tense: This is used for events that will happen in the future.
(C) Immediate past tense: This is correct because reports describe events that have already occurred.
(D) Present continuous tense: This is used for actions happening right now, not for past events.
Step 3: Conclusion.
Since report writing narrates events that have already occurred, it is written in the immediate past tense. Hence, the correct answer is (C).
Final Answer:
\[
\boxed{(C) \, \text{Immediate past tense}}
\]