Explanation:

- The sentence "The hunchback was being laughed at by everyone" is in the past continuous tense. It describes an ongoing action in the past.

- Option 1: Everyone was laughing at the hunchback.

- This is also in the past continuous tense. It fits well with the original sentence and describes an ongoing action in the past.

- This is the correct choice.

- Option 2: Everyone is laughing at the hunchback.

- This is in the present continuous tense. It describes an ongoing action happening now.

- Option 3: Everyone laughed at the hunchback.

- This is in the simple past tense. It describes a completed action in the past.

- Option 4: Everyone laughs at the hunchback.

- This is in the simple present tense. It describes a general or habitual action.