As part of a class project, a college student wanted to estimate the proportion of students at his college that owned a red car. To estimate this proportion he went to a large student parking lot during the middle of a class day. He found that 325 out of 1037 cars (31%) were red. This sample is best described as

Select one:

A convenience sampleA simple random sampleA volunteer response sampleA stratified random sample with color of car as the strata