The CMRR of a typical IC OPAMP is

The correct answer is A. 70 dB.

Common-mode rejection ratio (CMRR) is a measure of an op-amp’s ability to reject common-mode signals. Common-mode signals are signals that are present on both inputs of the op-amp. CMRR is usually specified in decibels (dB). A higher CMRR indicates that the op-amp is better at rejecting common-mode signals.

A typical IC op-amp has a CMRR of 70 dB. This means that the op-amp can reject common-mode signals that are 70 dB lower than the differential-mode signals. For example, if the differential-mode signal is 1 V, the op-amp can reject common-mode signals that are as high