Unlike Older Bonds, Which Were Printed on Paper with Mail-In

Unlike older bonds, which were printed on paper with mail-in coupons used to trigger interest payments, bonds today are mostly recorded in a different way. Which statement best describes how bond details are recorded for most bonds today?

A) Bonds are recorded electronically.
B) Bonds are recorded electronically and on paper.
C) Bonds are recorded on paper, which both parties keep, and electronically.
D) Bonds are recorded electronically, but coupons are still used to collect interest.