Final answer:
The statement is true; William of Orange was indeed married to James II's daughter, Mary, and they were both in line for the throne of England, later becoming King William III and Queen Mary II.
Step-by-step explanation:
The statement that William of Orange was married to James II's daughter, Mary, and was also in line for the throne of England is true. William of Orange, a sovereign Prince of the Netherlands, married Mary, who was the Protestant daughter of the Catholic King James II of England. Due to the fact that James II was widely unpopular due to his Catholic faith and autocratic rule, and because William and Mary were Protestants, they were invited by a group of nobles to take the throne in what is known as the Glorious Revolution. They became joint sovereigns as King William III and Queen Mary II. This marked one of the most significant moments in British constitutional history, establishing a constitutional monarchy which limited the powers of the monarch and ultimately led to a parliamentary system of governance.