Explanation:

Let's analyze each statement to determine its truthfulness based on computer science definitions: \nOption (a) Byte is a single digit in binary number: This is incorrect. A single digit in a binary number is called a 'bit' (binary digit), not a byte. A byte is a collection of bits. \nOption (b) Bit represents a group of digital numbers: This is incorrect. A bit represents a single binary digit ($0$ or $1$), which is the most fundamental unit of information. It does not represent a 'group of digital numbers.' \nOption (c) Byte is an eight digit binary number: This is the correct statement. In computer science, a byte is a unit of digital information that most commonly consists of eight bits. An eight-bit binary number can represent $2^8 = 256$ different values, ranging from $00000000_2$ to $11111111_2$. Therefore, a byte is essentially an eight-digit binary number. \nOption (d) Bit is an eight digit binary number: This is incorrect. As established, a bit is a single binary digit. An eight-digit binary number is a byte. \nOption (e) None of these: This is incorrect because option (c) is a true statement.