Select the segment of the sentence that contains the grammatical error. If…

Concept: When two subjects are joined by correlative conjunctions such as 'either...or', 'neither...nor', or 'not only...but also', the verb must agree in number with the subject nearer to it (the proximity rule) - not with the subject farther away, and not with a plural formed by simply combining both subjects.

Application: In 'Either my sister or my brother are coming to the parents' meeting,' the two subjects joined by 'either...or' are 'my sister' and 'my brother' - both singular nouns. Because 'my brother' is the subject nearer to the verb, the verb must be singular: 'is coming', not 'are coming'. The segment 'are coming to the parents' meeting' therefore contains the error.

Contrast:

• 'Either my sister' - a bare noun phrase with no verb, so it cannot itself carry a subject-verb agreement error.

• 'or my brother' - likewise a bare noun phrase with no verb, so it cannot carry the error either.

• 'No error' - incorrect, since a real mismatch exists between the verb and the nearer subject.

Cross-check: applying the same proximity rule with the subjects reversed ('Either my brother or my sister ___ coming') still calls for a singular verb, confirming the rule is about nearness, not about which noun is listed first. The corrected sentence reads: 'Either my sister or my brother is coming to the parents' meeting.'