Which encoding standard is described as a variable-length encoding that expresses each byte in hexadecimal and prefixes with %?

• A. UTF-8
• B. Base64 Encoding
• C. URL Encoding
• D. Hex Encoding

Answer: (C)

URL encoding, or percent-encoding, uses a percent sign followed by two hexadecimal digits to represent each byte that needs to be transmitted in a URL. Because characters can be represented by multiple bytes in UTF-8, the encoded form can have a variable number of %XX sequences, making it variable-length. This directly fits the description of a variable-length encoding that expresses each byte in hexadecimal and prefixes it with %. Other options don’t match: UTF-8 is a byte-encoding for characters and doesn’t rely on %XX sequences; Base64 encodes binary data using a different ASCII set; Hex encoding would show bytes as hex digits without the % prefix.