In each of the following cases, the variable represents one way that a sample can be stratified

Question:

In each of the following cases, the variable represents one way that a sample can be stratified in a study. For each variable, list some strata into which the variable can be divided.
a. Age of respondent (person)
b. Size of company (sales volume)
c. Size of retail outlet (square feet)
d. Geographic location
e. Occupation of respondent (person)
f. Type of business (company)