What kind of bias is exhibited on the following questions?

Choices: Undercoverage, Nonresponse, Interviewer Effect, and Voluntary Response Sample

1. A radio station program host invites the listeners to telephone call the radio station on live broadcast about their opinions on the City government's move to provide bicycle lanes and public bike racks.

2. A researcher who is studying about a certain polyphenol oxidase produced by apples systematically chooses only the healthy-looking apples because they yield higher amounts of extracts.

3. Carefully chosen to be part of a sample, busy office workers never accomplished the survey questionnaire because it was 20 pages long.

4. To generate public opinions about the current administration, a Statistician working for a media company asks respondents the simple question: "What don't you like about the current administration?"