Which advantage does the bidirectional Cisco QSFP 40-Gbps BiDi transceiver provide?

A.	It supports link lengths up to 10 km over single-mode fiber with duplex line card connectors.
B.	It supports a breakout connection with a 40-gigabit QSFP port on one end that connects to four 10-gigabit SFP+ ports on the other end.
C.	It provides dedicated fabric-extender transceiver modules that connect to fabric links (that is, links between a fabric extender and a parent switch).
D.	It enables the reuse of the existing 10-gigabit duplex MMF infrastructure for migration to 40 Gigabit Ethernet connectivity.