Read each sentence to find out whether there is any grammatical or idiomatic…

Concept: In subject–verb agreement, a verb must match its true subject in number, and the verb tenses across a single narrated sequence must stay consistent. A prepositional phrase that sits between the subject and the verb (“of the boat”) never changes the subject’s number — you identify the head noun and ignore the modifier.

Application: The head subject of this sentence is “The skipper”, which is singular; “of the boat” only describes the skipper and does not govern the verb. The narration is in the past tense, shown by “made it safely into the port”. So the verb describing what the skipper did must be singular and past: “guided”.

The segment reading “boat guide the vessel” uses the bare plural/base form “guide”, which neither agrees with the singular subject “skipper” nor matches the past-tense “made”. The correct form is “guided” (or, in a present-tense frame, “guides”). This segment carries the error.

Cross-check of the other segments:

• “The skipper of the” — a correct noun phrase; the singular subject and its modifier are well formed.

• “through the storm and made” — correct; “made” is the proper past-tense form and fixes the time frame as past.

• “it safely into the port” — correct; the pronoun and the prepositional phrase are idiomatically sound.

• “No Error” does not apply, because the verb-form mismatch in “guide” is a genuine grammatical error.

Hence the error lies in the segment “boat guide the vessel” — “guide” should be “guided”.