David’s parents have noticed that he is wearing clothes that have the marijuana leaf symbol and he has a collection of beer cans in his room. they have overheard david joking with his friends about drugs, but when they try to talk to david about drugs, he becomes angry and leaves the room.
david’s behavior indicates that he has a problem with drugs or alcohol primarily because of his:

a) identification with the drug culture.
b) signs of physical deterioration.
c) dramatic changes in school performance.
d) changes in behavior.

a. identification with the drug culture

Explanation:

David's likes and preferences such as marijuana leaf symbol on his clothes, collection of beer cans and jokes about drug indicate his mind's working. He thinks and talks about drug or alcohol. More importantly, David's anger over his parents trying to talk about drug shows there is some truth. All the activities of David including the room in anger shows he does not like to talk about drug or alcohol, a normal tendency among youth to hide such habits in the beginning. David identifies himself with drug culture due to his cloths, his likes, and his behavior.

it´s related to his charming character.

beauty is not everything, although we can joke that girls only care about the physical or material aspect, the truth is that a real woman looks at more important things, besides intelligence and personality, there are other attitudes that make irresistible to men who are 'unattractive'.

for example develop your sense of humor.

good question. i'll be looking into that. (this is a joke sir)