failed assumptions

This information will be used for the next two questions: You are curious why some apartments in West Campus cost more to rent than others. So you sample 30 one-bedroom apartments from across different West Campus apartment buildings and record the monthly rent (in dollars), along with the following explanatory variables: Area - square feet of living space in the apartment Age - how many years old the building that contains the apartment is Parking - whether or not the apartment comes with a parking space You ran a linear regression model predicting monthly rent and including the main effects of all three explanatory variables. Question: If the one-bedroom apartments in your sample were selected because they were being rented by your friends, which assumption (if any) would have been violated? O None of these assumptions would have been violated. O the independent observations assumption O the normality assumption O the random sample assumption