Explanation:

The acronym USB stands for 'Universal Serial Bus'. This is a widely adopted industry standard that defines the cables, connectors, and communication protocols used for connection, communication, and power supply between computers and electronic devices. The 'Universal' aspect highlights its broad applicability across various device types, and 'Serial Bus' refers to its method of data transmission, where data bits are sent sequentially over a single line. Option (a) 'User System Board', (b) 'Unique Static Base', and (d) 'Unique Systematic Bus' are all incorrect and do not correspond to any recognized computer terminology or standard. The 'Universal Serial Bus' standard revolutionized peripheral connectivity by providing a single, standardized interface for a vast array of devices, from keyboards and mice to printers and external storage.