(a) Whoever sells any marijuana to a person who has not reached the age of 21 years, or sells to any person of more than such age any marijuana knowing that such marijuana is bought for a person who is less than 21 years of age shall be subject to a civil penalty not less than $250 nor more than $500.
(b) In any enforcement action under this section, it is an affirmative defense that the individual who is under 21 years old presented identification, with a photograph of such individual affixed thereon, to the accused and the identification set forth information which would lead a reasonable person to believe such individual was 21 years old or older.