The correct answer is C. His subordinate was punished by the Army chief.
The other options are incorrect because they do not accurately reflect the tense of the sentence. Option A, “His subordinate is punished by the Army chief,” is in the present tense, but the sentence is about an event that happened in the past. Option B, “His subordinate is being punished by the Army chief,” is in the present progressive tense, but the sentence does not indicate that the punishment is ongoing. Option D, “His subordinate was being punished by the Army chief,” is in the past progressive tense, but the sentence does not indicate that the punishment was ongoing.
The sentence “The Army chief punished his subordinate” is in the simple past tense, which indicates that the punishment happened at a specific point in time in the past. The simple past tense is used to talk about events that happened in the past and are not ongoing.