Which of the following statements are true about structured and unstructured interviews?

a$.$ A structured interview involves a panel of interviewers whereas an unstructured interview involves only a single interviewer

b$.$ A structured interview involves an HR representative whereas an unstructured interview does not involve an HR representative

c$.$ Structured interviews are considered more reliable compared to unstructured interviews.

d$.$ Structured interviews are considered more valid compared to unstructured interviews.

e$.$ None of these apply