D providing more cost effective alternatives to prescribed drugs
Patient non-compliance
he did not comply with the prescribed amount of antibiotics.
You can prevent the spreading of communicable disease by following through with Option C) avoiding sharing personal items, like toothbrushes. All of the other options can lead you to getting a disease, if you ignore hygiene you will never be clean, and if you avoid insect repellent you might get a disease from a bug, and if you cough/sneeze without covering your nose/mouth then you may catch a cold. Therefore pointing to the correct answer option C.
I hope this helps! Have a good day!