Solution: Choice C is correct.

Since the maximum occupancy is 1 person for every 7 square feet.

Therefore, the maximum occupancy for a hall that is 14,721 square feet is 14721/7 = 2103 persons.

As the question asks as to how many more people than 1000 expected can attend the concert.

Therefore additional 2103 – 1000 = 1103 ≈ 1100 can attend the concert without causing a fire hazard.