Raoul is a network administrator and is planning the setup of a newly expanded network. He considers creating a star network, in which $\_\_\_\_\_\_.$

a$.$

each device is attached to a central device, such as a switch

b$.$

data travels from one device to the next in a clockwise fashion

c$.$

all devices attach to a central cable that carries the data

d$.$

all devices interconnect directly with one another