A hi school is conducting a survey to see how many students have part time jobs. Would this sample be biased or unbiased?

The sample: 100 random students in the school parking lot

It would be biased because one would assume that students can get to school by means other than those that put them 8n the parking lor. (Parking lot = car drivers who would be the only students sampled.). Others may ride to school by either parent or school bus who could drop them off somewhere else or possibly walk to school. The freshmen/sophomores would be excluded generally as they would be too young to drive altogether