Q.Which of the following best defines 'Law' in the sense understood by jurists such as John Austin?

Jurists distinguish "law" in the strict legal sense from morality, religion, and etiquette by one key test: is the rule made/recognised by the State and enforced through its courts, with a sanction for breach?

John Austin's "command theory" describes law as a command of the sovereign, backed by a sanction, habitually obeyed by the people — this is exactly what option (b) restates in plain language. Options (a), (c), and (d) each describe something that MAY influence behaviour, but none of them is enforced by the State through its courts, so none of them qualifies as "law" in the legal sense.

Why (b) is correct: John Austin defined law as a command issued by a sovereign political authority, backed by a sanction, and habitually obeyed by the people it governs. Sir John Salmond similarly defined law as the body of principles recognised and applied by the State in the administration of justice. Both definitions converge on the same core idea that option (b) captures precisely: law is a body of rules of conduct that is (i) recognised by the State, (ii) enforced by the State (through its courts and administrative machinery), and (iii) applicable to regulate human behaviour in society.

Why the distractors are wrong:

• (a) describes morality, not law. Moral principles guide conduct, but breach of a moral principle attracts only social disapproval, not a State-imposed legal sanction — and morality is followed voluntarily, whereas law is enforceable even against an unwilling person.
• (c) describes religion. Religious commandments may well shape a society's moral and even legal norms over time, but a religious commandment becomes "law" only if the State formally enacts or recognises it as such — until then, it binds only the conscience of a believer, not everyone within the State's jurisdiction.
• (d) describes social etiquette — customs of polite behaviour with no legal sanction attached at all. Breaching etiquette may cause embarrassment, but it invites no fine, imprisonment, or court action.

A common mistake is treating any widely followed rule — whether moral, religious, or a social custom — as automatically being "law." Remember the deciding test: is the rule made or recognised by the State, and is it enforceable through courts with a sanction for breach? If the answer to either part is no, it is not law in the strict legal sense, however important or widely followed it may be.