Concept:Low-level languages communicate with the computer using the machine's native number system.Explanation:Low-level languages, such as machine code and assembly language, work directly with the processor.The computer hardware recognises only two electrical states: on and off.These states are written as 0 and 1, forming the binary number system, which has base 2.Hence, low-level languages use the binary base system for data and instructions.Answer:B. Binary