Hello teachers, experts and natives,<br/><br/>Which one of the below is the correct option to complete the sentence?<br/><br/>I think I have seen someone at the window, ---------.<br/><br/>a- it was a man with a black hat and glasses<br/><br/>b- but I am not sure who they are<br/><br/>In option b someone refers to they. Is this correct?<br/><br/>In option a, I think it is possible to use simple past here. Am I wrong?<br/><br/>Thanks in advance.