An interview conducted by a research writer would be a source.
secondary
reliable
primary
tertiary

It is a Secondary source because it is conducted by the conductor.

secondary is a correct option.

Explanation:

primary source: source which has the original source of information. It is a source of which has been created when the study is done.Secondary source: in which analysis is done based on the primary source, In this original information analyzed and arranged after that evaluation is done. In this case an interview conducted by a research writer would be a secondary source because the analysis is done based on the primary data.tertiary source: It is a distillation of the information obtained from both primary and secondary sources.