I think its d. the client has to be able to be comfortable with the exercise. idk if that's correct, but itd be my opinion.
Answer:
You have to start creating a portfolio and reach out to agencies and submit your work. Once you do start modeling this adds to your credintials and will help you find better work and agencies. Please do be careful to the people and companies you reach out. It's best to go through the process with someone you know who works in the modeling industry or simply your parents. As to what teen modeling agency is the best, it depends on where you live.
