Which of the following BEST describes the difference between Ultra-ATA and Ultra-ATA 66?

A.
Ultra-ATA 66 uses an 80-pin ribbon connector while Ultra-ATA uses a 40-pin ribbon connector.

B.
Ultra-ATA 66 supports multiword direct memory access (DMA) mode 3 while Ultra-ATA supports multiword direct memory access (DMA) modes 1 and 2.

C.
Ultra-ATA supports Programmed Input/Output (PIO) modes 0, 1, and 2 while Ultra-ATA 66 supports Programmed Input/Output (PIO) modes 3 and 4.

D.
Ultra-ATA supports a maximum data transfer rate of 66 MBps while Ultra-ATA 66 supports a maximum data transfer rate of 100 MBps.

Explanation:
Ultra ATA 66 increased the maximum data transfer rate of the bus by doubling the number of conductors in the IDE signal cable to 80.
Incorrect
Answers:
B: Support for multiword direct memory access (DMA) mode 3 was introduced in Ultra-ATA while support for multiword direct memory access (DMA) modes 1 and 2 war introduced in ATA-2.
C: Support for Programmed Input/Output (PIO) modes 3 and 4 was introduced in ATA-2 while support for Programmed Input/Output (PIO) modes 0, 1 and 2 war introduced in the original ATA specification.
D: Ultra-ATA, also known as Ultra-ATA 33 has maximum transmission rates of 33 MBps while Ultra-ATA 66 has maximum transmission rates of 66 MBps.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 168-173.