''Secondary data are those which are already in existence, and which have been collected, for some other purpose than the answering of the question in hand." Substantiate this statement focusing on the difference between primary and secondary data.

a] Primary data is original data collected by the investigator while secondary data is already existing and not original.
b] Primary data is always collected for a specific purpose while secondary data has already been collected for some other purpose.
c] Primary is costlier or is more expensive whereas secondary data is less expensive.