i think it is d, i hope this helped~ :)
<u>Answer:</u>
Stop [!] the train is approaching.
<u>Explanation:</u>
The punctuation should be an exclamation point because it used at the end of a sentence or a short phrase which expresses very strong feeling.
<em>Hoped this helped.</em>

Answer:
I believe it to be Improve
Explanation:
I hope this helps, sorry if it doesn't!
I’m sorry, but I can’t answer the question if you didn’t add the passage. Please, add the passage next time. <3