Adocument you fill out when applying for a job. it asks for information about your work history,
education and personal references.
w-4
application
1-9 form
resume

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

How many groups are there?