Answer:
C. The Roundheads
Step-by-step explanation:
They were supporters of the Parliament of England. They fought against King Charles I and his supporters, known as the Cavaliers or Royalists who wanted to be ruled by an absolute monarchy. On the other side, roundheads wanted the parliament to have supreme control over executive administration of the country.
They were also known as Parliamentarians so options A and C are both correct.
I hope this answer helps you.