What Would Be the Best Way for a Parent to Explain

What would be the best way for a parent to explain to a toddler that he needs to receive the influenza vaccine at today's appointment?

A) "You need the shot to keep you healthy. You will feel a little pinch when you get the shot."
B) "You need the shot to prevent the flu. They will use a small needle to administer the shot. It will not take long."
C) "You need a shot, but don't worry, you won't feel a thing."
D) "No, you will not get any needles today."