A free cholesterol screening program is set up in the downtown area during lunch hour. Individuals can walk in and have their cholesterol measured for free. One hundred seventy-three people use the service, and their average cholesterol is 217 mg/dL. The value 217 is an example of .

A sample probably containing bias and undercoverage.

Explanation:

This type of survey is probably a bias survey and undercoverage. This is because the survey was limited upto the people who work into that area.

The people who do not live in that area would be able to participate in the survey, the people who do not go to office would not be able to take part in the survey. The people who work at night shifts are also not eligible for the survey.

The people who stay at house would also be not able to take part in the survey and this is how the survey is said to be biased and undercoverage.

the answer would be  

c. neighborhood watch

hope this .