Answer:
A) Door-in-the-face technique
Step-by-step explanation:
In sociology, the door-in-the-face technique is a clever method to persuade someone. The person starts by making a request that is way too unrealistic, so the other persons involved usually deny it. After this denial, the person now makes a more realistic request, which was what he/she originally wanted, so because it is more understandable or realistic, people are more likely to agree to it.
In this case, Manuel is applying the Door-in-the-face technique as he starts asking his parents for something a bit unreasonable: a permanent subscription to HBO, which they refuse to because it seems to be a big amount of money. Then, he asks for something that was what he originally wanted, "only" $15 to go to the movies. His parents think this is far more reasonable than the HBO subscription, so they agree to it.