What is different between AT and ATX power supplies?

 A.     They are identical except for their shape.
 B.     AT supplies use a single P1 power connector while ATX uses P8 and P9.
 C.     AT supplies use P8 and P9 power connectors while ATX uses a single P1 connector.
 D.     AT power supplies run on 120V AC current while ATX uses 220V AC

Ans:  C