Doing personal interviews with holiday shoppers at an indoor mall is an example of research.
a. professional
b. interpersonal
c. secondary
d. primary

Doing personal interviews with holiday shoppers at an indoor mall is an example of D. PRIMARY research.

A primary research is any type of research wherein the researcher personally goes out and collects data. The researcher can personally conduct surveys, interviews, observations, and ethnographic research. Results from these activities are gathered primarily by the researcher.