1) Drought conditions must be taken very seriously. (2) Unfortunately, many people ignore conservation efforts until local authorities impose watering bans. (3) If the county's residents would stop washing their cars, irrigating their flower beds, and running half-full dishwashers, then the bans might not be necessary. (4) It is important that everyone realize, that a limited water supply must be shared wisely.

Which sentence contains a punctuation error?
A) sentence 1
B) sentence 2
C) sentence 3
D) sentence 4