Which narrator is most clearly omniscient? O A. Vicente learned that opening a candy shop would be no easy task,
but that wouldn't stop him.
B. The speaker felt his knees shaking. However, no one in the
audience even knew he was nervous.
C. "Stop, thief!" the guard shouted, but the thief was too quick and
made it over the castle walls.
O D. Ting looked across the table and noticed the frown on her date's
face. Something must be wrong.

B. The speaker felt his knees shaking. However, no one in the  audience even knew he was nervous.

Explanation:

An omniscient narrator knows everything that happens before the story, during the story, after the story. The key pointer is the narrator knows every character's thoughts and feelings.

A. Vicente learned that opening a candy shop would be no easy task,

but that wouldn't stop him.

The narrator is only discussing Vicente's thoughts, so this could be first-person narration.

B. The speaker felt his knees shaking. However, no one in the

audience even knew he was nervous.

The narrator talks about the thoughts of both "the speaker" and the audience, so the narrator is omniscient.

C. "Stop, thief!" the guard shouted, but the thief was too quick and

made it over the castle walls.

This could be any third-person objective or limited narration. It's like similar to watching a movie; you aren't told what the characters are thinking.

D. Ting looked across the table and noticed the frown on her date's

face. Something must be wrong.

This could be first-person narration since we only know the thoughts for one character, Ting.

faulty parallelism is a grammar construction where there is no balance in the parts of a sentence they have a similar meaning but the grammar structure is not equivalent.

the correct version of this faulty parallelism in the sentence is:

jefferson wrote the declaration of independence, and he was the nation's third president.

the problem with the first version is that the sentence:

"jefferson was both the writer of the declaration of independence"

presents jefferson as both a subject and an agent for the verb "write" because if he was "the writer" then the declaration of independence was written by him, besides that fact, the sentence presents a dependent clause.

while the second sentence:

he was the nation's third president.

presents a basic subject+verb+object structure

so, to give a proper balance to the structure, or better said, to give a parallel structure, we must write a basic s+v+o structure in both sentences:

jefferson wrote the declaration of independence, and he was the nation third president.

the sound a train makes as it blows it horn is the correct answer i believe