Answer,
A.nicotine gum
Explanation,
A nicotine gum is a type of chewing gum that takes nicotine to the body.Nicotine is delivered to the blood stream through absorption of the tissues of the mouth.It is used to help smokers to stop smoking by replacing nicotine that they usually get from tobacco products.It helps to lessen cravings of tobacco.Users of the gum gradually reduce their nicotine dosage until they can no longer have cravings.