Which of the following is NOT a method of error correction in wireless communication?

Multiplexing is a method used to combine multiple signals into one signal over a shared medium. Its primary focus is on efficiently utilizing the communication channel and enabling simultaneous transmission of different data streams. While it plays a crucial role in enhancing the capacity and efficiency of communication systems, it does not provide any form of error correction.

In contrast, methods like parities, checksums, and Reed-Solomon coding are specifically designed for error detection and correction. Parities add a simple binary digit to ensure an even or odd count of bits, making it possible to detect single-bit errors. Checksums create a numerical value based on the data being transmitted, allowing for verification and detection of errors during transmission. Reed-Solomon coding is a more advanced form of error correction that can correct multiple errors in a block of data.

Thus, the focus of multiplexing on data channel optimization distinctly categorizes it as a method unrelated to error correction, making it the correct answer to this question.