What Does Karl Weiss Mean When He Advises Marketers to "Triangulate

Multiple Choice

What does Karl Weiss mean when he advises marketers to "triangulate" research methods?

A) Do each survey three different times.
B) Repeat the same research with at least three different populations.
C) Have at least three experts interpret the data.
D) Use a multiple research methods to investigate a research question.
E) Use primary research before collecting secondary research.