A child is diagnosed with bacterial conjunctivitis and is prescribed topical antibiotic therapy. The child's mother asks when he can return to school. Which response by the nurse would be most appropriate?

"You need to wait until you finish the entire prescription of antibiotic.”.

"Once the drainage is gone, he can go back to school.”.

"You can send him to school this afternoon after his first dose of antibiotic.”.

"He needs to be symptom-free for at least 72 hours.”. — . . .