To estimate the proportion of city residents who shop online, a researcher visits a mall on a weekday morning and asks people she encounters to share their experiences with online shopping, including this question: "Do you shop online at least once each week?" The results show that 32% of shoppers shop online at least once per week. Which of these describes a likely source of bias present in the survey results? Response bias may be present because people may not be truthful with their responses.

Question wording bias may be present because the question asked may exclude important information.

Nonresponse bias may be present because people in a mall may not want to answer questions.

Undercoverage bias may be present because people in the workforce and many younger people could be excluded.