Natasha conducted a survey to determine how many of the 215 workers in her office building use public transportation to get to work. She surveyed 30 randomly selected workers who entered the office cafeteria throughout the day. Of the 30 workers surveyed, 9 used public transportation to get to work.
Which change to Natasha's survey process would make the data more reliable?

A. Ask a randomly selected sample of people who use public transportation whether their office is in the building.

B. Use a different sample size so the predicted number of workers who use public transportation is a whole number.

C. Have workers complete a written survey so there is a written record of the responses.

D. Randomly select the sample in the lobby of the building so workers who do not enter the cafeteria can be included.