Mayer High School's austerity committee wants to estimate the proportion of students that are pleased with the cleanliness of the campus. They consider two methods of obtaining a sample of 400 students from the 2,500 students at the school. Part A: To make the process easier, the committee considers surveying the first 400 students who enter the gym during the school's first pep rally. Identify the type of sampling method proposed and discuss why this sampling method might be biased. Part B: The second method the committee is contemplating involves using a random number generator app to choose a simple random sample of 400 students from a list of 2,500 student names. How could they implement this method?