Explain why human beings decide to get addicted in smoking from both 1) classical and 2) behavioral economics perspectives by addressing their differences in rationality assumptions and views for human nature

a) Explain why human beings decide to get addicted in smoking from both 1) classical and 2) behavioral economics perspectives by addressing their differences in rationality assumptions and views for human nature. (Max. 400 words) 
b) Explain what research approach that a behavioral economist may use to study addiction in smoking and how this research approach would be different from that of a classical economist. (Max. 200 words)