The city council hired three college interns to measure public support for a large parks and recreation initiative in their city. The interns mailed surveys to 500 randomly selected participants in the current public recreation program. They received 150 responses. Which of the following is the appropriate sampling frame in this scenario? The 150 people that responded O All participants in the city's recreation program O The participants that support the initiative O All members of the community O The 500 people who got the survey