C. Mainframe computers
EBCDIC (Extended Binary Coded Decimal Interchange Code) is an 8-bit character encoding used mainly on IBM mainframe computers and AS/400 systems. EBCDIC is an older character encoding standard that was widely used in the mid-20th century, but has largely been replaced by more modern encoding standards, such as ASCII and Unicode.
Option A (Minicomputers), Option B (Microcomputers), and Option D (Supercomputers) are incorrect because EBCDIC is not commonly used on these types of computers.
Therefore, the correct answer is C) Mainframe computers.