Final answer:
It is true that William of Orange was in line for the throne of England through his marriage to Mary, the daughter of James II. They ruled as co-monarchs following the Glorious Revolution, which cemented Protestant rule in England.
Step-by-step explanation:
The question pertains to William of Orange's eligibility for the throne of England due to his marriage to James II's daughter, Mary. It is true that William of Orange was in line for the throne of England. William III, as he would become, was married to Mary II, and together they reigned as co-monarchs after the Glorious Revolution.
This period saw significant constitutional change, including the drafting of the Bill of Rights 1689, which would underpin the constitutional monarchy that Britain has today. William and Mary's ascension was essential in cementing Protestant rule in England, in contrast to James II's Catholic faith, which had concerned many in England at the time.