It is difficult to write a PSA or a Public Service Announcement that operates in just sixty (60) seconds because you have to consider a lot of factors into writing it. First, you consider what message you want to convey. Second, you consider what kind of audience you're targeting. Lastly, you have to make sure that the PSA will effectively convey the message to the target audience in such short amount of time.
The bolded pronoun in the given sentence is the word "which". This pronoun is an example of an interrogative pronoun. Interrogative pronouns are pronouns that are used to introduce a question. The antecedents of interrogative pronouns are unknown because it is what is being asked in the sentence that is missing.
the answer is b i know because i just did it and i know for afact this right