Question 40: Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions: What happened in that city were a reaction from city workers, including firemen and policemen who had been laid off from their jobs.
Knowledge of subject and verb harmony
That/what + S + V + V (singular)
=> The answer is B (were => was)
What happened in the city was the reaction of workers including firefighters and policemen who were fired.