Question

which statement is not a rule for the data source for the mail merge?
the top line must contain the names of the fields being using in the merge.
each field name in the data source must be unique.
field names can be any size.
field names should start with a letter.

Explanation:

Mail merge data source rules: top - line field names (required), unique field names (necessary for proper data handling), field names starting with a letter (common naming convention). However, field names have a limit (usually not more than 64 characters in many applications).

Answer:

Field names can be any size.