Explanation:

Among the given options, ASCII (American Standard Code for Information Interchange) is a widely used character encoding standard for electronic communication, forming the basis for many modern encodings like Unicode. EBCDIC (Extended Binary Coded Decimal Interchange Code) is another significant encoding, primarily used on IBM mainframe operating systems. Option (a) "ASCII and EBCDIC" is the most comprehensive answer, acknowledging both as major coding systems that are still in use in various contexts, even if Unicode is globally dominant today. Option (b) ASCII is widely used, but (a) includes another significant system. Option (c) EBCDIC is more specialized. Options (d) and (e) are incorrect.