An automobile manufacturer whose research revealed a desire for status drove most new car purchases probably knows this from collecting what category of primary data?

c) Repeated measures

Explanation:

Repeated measure designing is the design in which same variable's multiple measures are taken under different condition but on the similar subject.It can also be taken over different time period for researching.

According to the question.,Eric is using repeated measures design by researching on people's enjoyment wen drinking coffee, teas and milk at certain time.Thus study is on the similar subject with same participant with repeating act.

Other options are incorrect because research design is not based on posttest ,pretest or concurrent measures .Thus, the correct option is option(c).