The correct answer is “had.”
The sentence is in the past tense, so we need to use a past tense verb. “Was having” is the past progressive tense, which is used to describe an action that was in progress at a specific time in the past. “Are having” is the present progressive tense, which is used to describe an action that is happening now. “Have” is the simple present tense, which is used to describe an action that happens regularly or habitually. “Should have” is the past modal verb, which is used to express regret or disapproval about something that did not happen.
In this case, we are asking about something that happened in the past, so we need to use a past tense verb. “Had” is the simple past tense of the verb “to have,” which is used to describe an action that happened at a specific time in the past.
Here are some other examples of how the verb “to have” is used in the past tense:
- I had lunch at noon.
- We had a lot of fun at the party.
- She had a bad day at work.
- They had a fight.
I hope this helps! Let me know if you have any other questions.