Caroline Needs to Research Information About Income and Age Distribution

Caroline needs to research information about income and age distribution in Fort McMurray, an urban service area in Alberta.The source of secondary data which would be most useful to
Caroline in terms of being easily accessible at a low cost is:

A) a door-to-door survey.
B) focus group interviews.
C) syndicated data.
D) sales invoices at public libraries.
E) census data.