A manufacturing company is looking to hire machine operators for its production facility. The company wants to ensure that candidates have the necessary motor skills and coordination to operate machinery safely and efficiently. Which of the following assessments would be most appropriate for evaluating the candidates' psychomotor abilities?

a$.$

A written aptitude test

b$.$

A personality assessment

c$.$

A structured interview

d$.$

A hands$-$on skills demonstration on using the machinery