B gives a step, that without other information gives no idea of what the result will be. . Similar to turn left. ---- and what? Go straight --- to do what? Use capital letters --- for what? to do what? . All the others state some aim.

B. Is a specific instruction (take a left) and not a topic. All the other options are more general topics of how to get somewhere.

Thank you so much, everyone who answered!!! :)

Topic sentences tell you what an article (or paragraph) is going to be about. Sentences A, C, and D are all sentences that imply they will give you directions to a location, but have no actual directions in the sentence. Sentence B gives you directions, but gives you no information about the destination and does not tell you anything about the sentences that follow it. For Sentence A, "here is how..." is a phrase that is almost always used to say that directions for doing something will be explained. Sentence B is part of the directions. Because you are told that this is "how-to", you know a sentence starting with the word "next" is not the first sentence. This will give you a clue, since topic sentences are usually the first sentence (though not always). In Sentence C, "let me tell you..." is used in pretty much the same way as "here is how..." from sentence A. Sentence D is a bit more difficult because saying "it is easy to..." can be followed by instructions on how to do a thing, but it could also just be a statement. I will say that this is not the easiest question. Picking out a topic sentence in English is much easier when you are reading something than it is with just a question.