Which disk interface standard includes support for up to eight peripheral devices?

The correct answer is C. SCSI.

SCSI stands for Small Computer System Interface. It is a standard for connecting peripheral devices to a computer. SCSI can support up to eight peripheral devices on a single bus.

IDE stands for Integrated Drive Electronics. It is a standard for connecting hard drives to a computer. IDE can support two devices on a single bus.

ESDI stands for Enhanced Small Device Interface. It is a standard for connecting hard drives to a computer. ESDI can support up to four devices on a single bus.

ST50G/412 is a specific model of hard drive. It does not have a standard interface.

Therefore, the correct answer is C. SCSI.