1 Byte contains-
Option 4 is the right answer.
In computer science a byte (pronounced “bite”, IPA: /baɪt/) is a unit of measurement of information storage, most often consisting of eight bits. In many computer architectures it is a unit of memory addressing.
Originally, a byte was a small group of bits of a size convenient for data such as a single character from a Western character set. Its size was generally determined by the number of possible characters in the supported character set and was chosen to be a submultiple of the computer’s word size; historically, bytes have ranged from five to twelve bits. The popularity of IBM’s System/360 architecture starting in the 1960s and the explosion of microcomputers based on 8-bit microprocessors in the 1980s has made eight bits by far the most common size for a byte. The term octet is widely used as a more precise synonym where ambiguity is undesirable (for example, in protocol definitions).