What is the best option to quit smoking?

Hello, my dad is trying (and determined) to quit smoking. Some choices that he is willing to take is Nicoteen Gum, Nicoteen Patch, Chantix, or Cold turkey (when you quit smoking without any help). Please pick the option and list positives and negatives about it.
Oh yeah, and just to let you know, my dad only smokes about 1-2 cigarrettes a day. So he’s not a "heavy" smoker. He’s just still addicted to it.