The correct answer is D. Machine code is both (b) and (c).
Machine code is a binary representation of instructions that a computer can understand and execute. It is also known as object code or machine language. Machine code is typically generated by a compiler or an assembler from a higher-level programming language such as C or Java.
Source code is the human-readable form of a computer program. It is written in a programming language that is easy for humans to understand. Source code is then compiled or interpreted into machine code, which is the binary representation of instructions that a computer can understand and execute.
The 0s and 1s that the computer can understand are the binary digits (bits) that make up machine code. Each bit can be either a 0 or a 1. A sequence of bits can represent a number, a letter, or an instruction.
Machine code is the lowest level of programming language. It is the only language that a computer can directly understand and execute. All other programming languages are higher-level languages that are translated into machine code before they can be executed by a computer.