What Is the Difference Between Structured and Unstructured Interviews

What is the difference between structured and unstructured interviews?

A) Structured interviews dictate specific questions. Unstructured interviews are more conversational and open ended.
B) Structured interviews have to take place in a particular time and place. Unstructured interviews can take place anywhere.
C) Structured interviews have answer choices that the respondent selects from.
In an unstructured interview, the respondent gives answers which the interviewer later codes into categories.
D) Structured interviews draw from a standard database of questions. Unstructured interviews are innovative, and ask new questions.
E) All of the above