Which is the critical, first step in the five$-$step marketing rThe U$.$S$.$Census is an example of:

a$.$

External secondary data

b$.$

External primary data

c$.$

Internal secondary data

d$.$

Internal primary data

e$.$

Non probability dataesearch approach:

a$.$

Presenting the findings.$$

b$.$

Defining the problem.

c$.$

Analyzing the data.

d$.$

Collecting data.

e$.$

Developing the research plan.