Read the following excerpt from a US court opinion:
```
that remand is discretionary with the court. 17 . This local rule provides in relevant part: [I]f a motion requires consideration of matters not established by the pleadings, the moving party at the time of delivery and service of its supporting brief shall file with the Clerk such evidentiary materials, including discovery materials and affidavits, as are being relied upon and have not previously been filed, and shall serve a copy of them upon each other party; such documents shall not be attached to the brief.... Documents must be identified and authenticated by affidavit.... 18 . Converting Ameritrade's motion to dismiss into a motion for summary judgment would preclude the possibility of Green voluntarily dismissing the action pursuant to Fed. R.Civ.P. 41(a n. 9 (8th Cir. 1997) . 20 . In such event, however, the case once
```
What is the most suitable continuation to the opinion? Your options are:
A. holding that court could consider prospectus that was not attached to complaint
B. holding that court may look both to complaint itself and to any documents attached as exhibits to complaint
C. holding court could consider a mortgage agreement not attached to the complaint in ruling on motion to dismiss because the complaint refers to the mortgage numerous times the mortgage is attached to this motion and is central to plaintiffs claims
D. holding that the court may consider an article not attached to the complaint in determining whether to dismiss the complaint because the article was integral to and explicitly relied on in the complaint and because the plaintiffs did not challenge its authenticity
E. holding that it was appropriate for the district court to refer to the documents attached to the motion to dismiss since the documents were referred to in the complaint
Reply with [A, B, C, D, E] only.