Final answer:
The claim that William of Orange, married to Mary, daughter of James II, was also in line for the throne of England is true. His marriage and lineage as a grandchild of Charles I allowed him to have a claim to the throne, which he pursued during the Glorious Revolution.
Step-by-step explanation:
The statement "Although William of Orange was married to James II's daughter, Mary, he also was in line for the throne of England." is True. William of Orange married Mary, the eldest daughter of King James II of England, which formed an important political alliance. This marriage was significant not only because of the alliance but also because William was a claimant to the English throne himself. William's claim was partly based on his marriage to Mary and also stemmed from his position as a grandchild of Charles I, making him a nephew of James II.
This connection became crucial during the Glorious Revolution of 1688, when William was invited by a group of English nobles to invade England and claim the throne, leading to James II's deposition and William, alongside his wife Mary, taking the throne as co-rulers. This event underscored the complexity of succession and the interwoven European royal family ties of the time.