What is the difference between ASCII and Unicode, and why is Unicode necessary?

• A. ASCII is used for fonts; Unicode for fonts.
• B. ASCII encodes a small set of characters (7-bit/8-bit); Unicode provides code points for a vast range of characters from many languages, enabling international text.
• C. ASCII stores data as binary, Unicode stores as text.
• D. ASCII supports many languages; Unicode supports only English.

Answer: (B)

The main idea is that ASCII covers a tiny set of characters, while Unicode covers a vast range of characters from many languages. ASCII uses 7 bits per character (with extended forms using 8 bits), giving space for about 128–256 characters—enough for basic English letters, digits, and punctuation. Unicode, by contrast, assigns a code point to characters from almost every writing system, plus symbols and emoji, so text from many languages can be represented in one system. In practice, ASCII characters are also valid Unicode code points, so ASCII is a subset of Unicode. Unicode is implemented through encodings like UTF-8 or UTF-16, which turn those code points into bytes for storage and transmission; UTF-8 remains compatible with ASCII for the ASCII range. This universality is why Unicode is necessary: it lets software store, render, and exchange multilingual text consistently across different systems. The other statements miss the essential point: ASCII isn’t about fonts, both systems encode characters as binary data, and ASCII does not support many languages while Unicode does.