Answer:
B. The speaker felt his knees shaking. However, no one in the audience even knew he was nervous.
Explanation:
An omniscient narrator <em>knows</em> <em>everything</em> that happens before the story, during the story, after the story. The key pointer is the narrator knows <u>every character's thoughts and feelings</u>.
<em>A. Vicente learned that opening a candy shop would be no easy task,
</em>
<em>but that wouldn't stop him.
</em>
The narrator is only discussing Vicente's thoughts, so this could be first-person narration.
<em><u>B. The speaker felt his knees shaking. However, no one in the
</u></em>
<em><u>audience even knew he was nervous.
</u></em>
The narrator talks about the thoughts of both "the speaker" and the audience, so the narrator is omniscient.
<em>C. "Stop, thief!" the guard shouted, but the thief was too quick and
</em>
<em>made it over the castle walls.
</em>
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.
<em>D. Ting looked across the table and noticed the frown on her date's
</em>
<em>face. Something must be wrong.</em>
This could be first-person narration since we only know the thoughts for one character, Ting.