A possible data for source that could be used when completing a mail merge could be all the above.
d. all the above
Step-by-step explanation:
Mail merge allows one to send a particular document to different individuals.
It is generally used in office environment where some information is to be communicated to a number of people. The information is attached by adding the data sources.
The information source is a report, spreadsheet or database that contains customized data, for example, names, locations, and telephone numbers.