Question

which of these is a placeholder in a document into which variable data is inserted during the process of a mail merge?
data source
main document
merge field
none of the above

Explanation:

In a mail - merge process, a merge field is a placeholder in the main document where variable data from the data source is inserted. The data source is the file (like a spreadsheet or database) that contains the variable data. The main document is the template (like a letter) where the merge fields are placed. So, the merge field is specifically the placeholder for variable data insertion.

Answer:

C. merge field