When Derek joined her , the door man unhooked the rope to let them through , still watching Lucy with undisguised lust as they walked in . A look of utter confusion shown on Derek 's features as they were granted entrance into the club . He draped an arm over Lucy 's shoulders and they made their way through the crowds of people . " So how 'd you do that ?
According to the above context, choose the best option to answer the following question.
Question: What may be the reason for Derek 's confusion ?
Options:
- He did n't understand how they were able to get in so fast .
 - He did n't understand why he was let in with her .
 - He did n't understand why they were there .
 - He did n't understand why he bothered coming .


He did n't understand how they were able to get in so fast .