A high school committee wants to estimate the proportion of students that are pleased with the cleanliness of campus. They consider two methods of obtaining a sample of 400 students from the 2500 students at the school. Part A: to make the process easier, the committee consider serving the first 400 students who enter the gym during the schools first Pepper alley. Identify the type of sampling method proposed and discussed by the sampling method might be biased.

Part B: The second message the committee is contemplating involves using a random number generator app to choose a simple random sample of 400 students from a list of 2500 student names. How could they implement this method?