The phrasing here is a bit vague, but I think your teacher means "your" in the sense that it is directed at whoever is taking the survey and not a specific single person. If it was directed at exactly one person, and one person only, then no statistics are needed. You can simply count the number of songs on the device and that's the end of that story. However, when it comes to multiple people, statistics is used to give an idea of how the population is overall. Recall that the sample is supposed to represent the population, assuming no biases are present. I'll assume that your teacher is aiming for the more broader definition of "your" and that's why this is a statistical question. Similar reasoning will apply for problem 3.
Unlike problems 1 and 3, this is not a statistical question. Why not? Because we know exactly how many feet are in 1 yard, and that will not change no matter what happens. It's simply a definition we set up earlier, and have stuck to. Having it change won't help things. Statistical questions address variables in which not only are allowed to change, but do so randomly (according to some pattern). Here we have 3 feet to a yard and no statistics are needed to address this.
Similar to problem 1. I'm assuming your teacher is asking a broader audience and not exactly one single specific person. In this case, the name of the favorite movie would be considered qualitative categorical data, and also considered nominal as well. We don't have ordinal data because movies cannot be ordered or ranked, as that is subjective. I'm not considering alphabetical order. We have a statistical question here for the broader audience because the variable "favorite movie" is allowed to change, and is subject to some degree of randomness. Hence the phrasing "random variable".
