An economist would like to estimate the proportion of young adults who have college debt. An online survey invites young adults to share information about their level of college debt. Which of the following describes the survey design and potential bias? This is voluntary response and is likely to overestimate the proportion of young adults with college debt.

This is voluntary response and is likely representative of the proportion of young adults with college debt.

This is voluntary response and is likely to underestimate the proportion of young adults with college debt.

This is a convenience sample and is likely to overestimate the proportion of young adults with college debt.