Concept:Istislah is an Islamic legal principle that bases a ruling on public interest or common good.
Explanation:Istislah is used by jurists when the Qur'an, Sunnah, and consensus do not offer a direct ruling.
Its root concept is maslaha, which literally means public interest or benefit.
Under istislah, the jurist chooses the option that protects the welfare of the whole community.
Therefore, any decision taken for the good of the public is correctly described as istislah.
Ijtihad is independent reasoning to deduce a rule, so it does not specifically mean a public-interest decision.
Jihad means struggle or striving in the way of Allah, not a public-interest ruling.
Urf refers to the customary practice of a people and is not defined by public interest alone.
Answer:B. istislah.