How many bits does ASCII use to represent characters?

ASCII (American Standard Code for Information Interchange) represents characters using a 7-bit binary number. This 7-bit structure allows for 128 unique combinations (from 0 to 127), which can represent standard English letters, digits, punctuation marks, and control characters. The choice of 7 bits was sufficient for the original purpose of representing basic English text and control signals necessary for communication in early computing systems.

While extended versions of ASCII do exist, such as ISO 8859-1 (Latin-1) and others that use 8 bits to accommodate more characters (256 combinations), the original ASCII specification is strictly 7 bits. This is a fundamental aspect of ASCII's design, ensuring it can universally represent essential characters across different platforms and devices.

The other options are based on misunderstandings about character encoding. For example, while 8 bits are used in some extended ASCII systems, the standard ASCII still functions on a 7-bit basis as its core foundation. Similarly, 6 bits would not provide enough combinations to represent all the standard ASCII characters, and 16 bits pertains more to Unicode or other encoding schemes designed for broader language support and special characters, far exceeding what ASCII was initially created for.