Pick out the right response
 Rahul, a 20-year-old student, had a sore throat and mild fever. He bought antibiotics without a doctor’s advice and stopped midway. Two weeks later, his condition worsened. Tests showed antibiotic-resistant bacterial infection. The doctor explained that incomplete courses cause resistance and advised proper hygiene and no self-medication.
 
i. What mistake did Rahul make before his infection worsened?
 
ii. Which infection type is antibiotics not effective against, even if Rahul had taken them properly?