which document gave the people of plymouth a form of self-government?

a.
iroquois league

b.
massachusetts articles

c.
mayflower compact

d.
godspeed constitution

It was the Mayflower Compact, because they were Pilgrims arriving to the "New World", and to make sure the government/leadership is clear and official, they had wrote the Mayflower Compact to declare and obtain self-government. =)
I hope I helped! =D

First document to establish one was the Mayflower Compact
so (D)Mayflower Compact