Which of the following is a difference between primary data and secondary data?
a. ?Primary data result in a mismatch between a researcher's unique problem and the purpose for which the data was collected, while secondary data result in no such mismatch.
b. ?Primary data can be maintained in secrecy, while secondary data are usually available to all interested parties for relatively small fees or free.
c. ?Primary data are inexpensive and save time and money, while secondary data are expensive and more time consuming.
d. ?Primary data are data that have been previously collected, while secondary data are data that have been collected for the first time.