Which of the following sentences is punctuated correctly?
A.
Clara chased the red, trolley which was racing away from her—down the bustling street.
B.
Clara chased the red trolley, which was racing away from her, down the bustling street.
C.
Clara chased (the red trolley) which was racing away from her down the bustling, street.
D.
Clara chased—the red trolley, which was racing away from her down the bustling street.

b is the answer

Explanation:

the red trolley us used here as just one thing so a is wrong , and it can't be placed in a bracket cause it is necessary in the sentence since it's what is being chased , and a dash and a bracket are both used for the same purpose so c and d is wrong

B is correct

Explanation:

The content between the two commas is not necessary but it is still good information that is relevant to the sentence. Content in brackets is not necessary to the sentence, so C is incorrect because the brackets contain the subject, which is crucial to the context of the sentence. D is incorrect because ‘Clara chased’ is separate from ‘the red trolley’, rendering the second part of the sentence a phrase and therefore not a sentence. A is incorrect because red and trolley are separated and therefore not a complete subject because they are supposed to be together.

there is an explationation of this on a site called crash   course world history 1

can you explain a little further maybe give multiple choice? ?