Final answer:
Commonly used cables for data transmission are Ethernet cables like Cat5 or Cat6, which have 8 pins, but not the 7-pin data cable or the 15-pin power cable mentioned in the options.
Step-by-step explanation:
The type of cable commonly used for data transmission is not the 7-pin data cable or the 15-pin power cable. Therefore, the correct answer to the question is d) Neither a nor b. Common cables for data transfer include Ethernet cables like Cat5, Cat6, and others, which typically have 8 pins and are used to connect devices to a network. For direct connections to storage devices such as hard drives or SSDs, SATA cables, which are usually 7-pin (but specifically designed for that purpose), are used.