Concept:Islamic law forbids certain close relatives in marriage, but a woman not listed as forbidden remains lawful.
Explanation:The permanent prohibitions in the Qur’an include foster mothers, foster sisters, and the father’s wife.
A Muslim man may not marry his foster mother because she is treated like his real mother.
He may not marry his late father’s wife because she is his stepmother.
He may not marry his foster sister because she is like his real sister.
However, marrying his late wife’s sister is permitted, provided both sisters were not married to him at the same time.
Thus, among the options, only the late wife’s sister is lawful to marry.
Answer:B. Late wife’s sister