Correct option is B
The primary advantage of a differential amplifier over a single-stage amplifier is its ability to reject common-mode noise. A differential amplifier amplifies the difference between two input signals while largely ignoring signals that appear equally on both inputs, such as environmental noise or ground loops. This ability is quantified by a high Common-Mode Rejection Ratio (CMRR), making it highly suitable for use in noisy environments and in the input stages of precision instruments like operational amplifiers and medical devices (ECG/EEG monitors).
