According to application procedures, which of the following cannot be inquired about?

In the context of application procedures, inquiries about an applicant's age can lead to concerns regarding age discrimination. The Age Discrimination in Employment Act (ADEA) specifically protects individuals who are 40 years of age or older from being discriminated against based on their age. Therefore, employers are discouraged from asking about age-related information in application materials or interviews, as this can create biases against older applicants or lead to unfair treatment based on age.

On the other hand, questions regarding work history, educational background, and references are typically relevant and permissible in assessing a candidate's qualifications and fit for a position. These areas provide significant insight into a candidate's professional experience, skills, and potential contributions to an organization.