Which sentence is correct when the jury members have differing opinions?

Concept

A collective noun — jury, team, committee, family, crew — names a group of people under a single label. English lets such a noun take either a singular or a plural verb, and the choice is settled by the sense intended rather than by the form of the noun. Grammarians call this notional agreement.

When the group is presented as one undivided body acting together, the singular verb is used. When its members are presented as separate individuals doing or thinking different things, the plural verb is used, together with the plural pronouns they and their. Whichever sense is chosen, the verb and every pronoun that points back to the noun must keep that same sense across the whole sentence.

Application

The stem fixes the sense, so the agreement follows in steps:

1. The stem states that the members of the jury hold differing opinions, so the noun is being presented as separate individuals rather than as one undivided body.

2. Under notional agreement, the separate-members sense requires the plural verb, and the pronoun pointing back to the noun must be plural as well — their, not its.

3. The sentence carrying both is "The jury were divided in their opinion." — the plural verb were with the plural possessive their.

4. Its predicate, divided in their opinion, states the disagreement the stem describes, so verb, pronoun and sense all agree, and this is the sentence that fits the situation.

Cross-check

Applying the same rule to the remaining sentences:

• "The jury has made a single decision." — the singular verb has made keeps the undivided-body sense throughout, so the sentence is well formed English; but it reports one agreed outcome, which is the united sense, not the situation of members differing.

• "The jury was unanimous in their decision." — the singular verb was takes the undivided-body sense while the possessive their takes the separate-members sense, so the two halves of one clause pull in opposite directions; unanimous also states complete agreement.

• "The jury is one." — the singular verb is asserts only that the body counts as a single entity, and the sentence says nothing about what the members think.

Grammar references draw the same contrast with a second collective noun:

The jury sentences work in exactly the same way. Because the stem places the jurors in disagreement, the plural-sense sentence — "The jury were divided in their opinion." — is the sentence that is correct here.