Answer: UNSTRUCTURED INTERVIEW.
Explanation: An unstructured interview can be defined as any formal face to face meeting for the assessment of a candidate or applicant format in which questions asked are not predetermined or prearranged. It is also known as a non-directive interview. Here, the interviewer ask questions which come to his/her mind on the spot.
This type of interview helps the researcher develop a real sense of a person's understanding of a situation.