B
Deuteronomy 24:1, "then let him" should be "and he." As the Savior explained in Matthew 19, Moses did not command divorcement. This statute is regulating the permission of divorce because of the hardness of their hearts.
No. Uncleanness can be attributed to not being a virgin or some other matter of unchastity. Consider reading on:
2And when she is departed out of his house, she may go and be another man's wife.
3And if the latter husband hate her, and write her a bill of divorcement, and giveth it in her hand, and sendeth her out of his house; or if the latter husband die, which took her to be his wife; 4Her former husband, which sent her away, may not take her again to be his wife, after that she is defiled; for that is abomination before the LORD: and thou shalt not cause the land to sin, which the LORD thy God giveth thee for an inheritance.
So the matter isn't about "if" the man wrote his wife a bill of divorcement, but when as the man would be directed by the Lord to do so for finding uncleanness in his wife, and thus instructing him not to take her back.. even when after this wife marries another and her second husband had died; the first husband still must follow the Lord in not taking her back in as his wife at all, because of the matter of uncleanness.