Unlike the Reentry Switcher in Your Text, the Cascading Switcher

Unlike the reentry switcher in your text, the cascading switcher has three busses per bank,

A) two "cascading" busses and a "key" bus.
B) two key busses and one "cascading" bus.
C) a "take" bus, a "dissolve" bus and a "key" bus
D) none of these. A cascading switcher has only two busses per bank.