Systematic desensitization is a kind of psychological treatment. When a stimulus that causes anxiety and fear appears in front of the patient, guide the patient to relax, so that the patient gradually eliminates anxiety and fear, and no longer has a pathological response to the stimulus. It includes rapid The desensitization method and contact desensitization method, etc. The former is when the therapist accompanies the patient in a situation where the patient is afraid, until the patient is no longer nervous. The latter is through demonstration, which allows the patient to gradually come into contact with the object they are afraid of. The purpose of overcoming fear. According to the above definition, if you want to treat a child who is particularly afraid of snakes, which of the following treatments is contact desensitization? ['After the child watches the touch of others, pick up and drop the snake, and then let the child gradually approach and touch the snake.', "Take your child to an indoor snake farm and watch a variety of snakes. Naturally, you won't be afraid anymore.", "Tell the child an interesting fairy tale about the snake, which will trigger the child's happy mood and gradually reduce the fear of the snake.", "Record the child's horrified expressions and actions after seeing the snake, and then show these videos to the child over and over."]