Which of the following measures indicates the proportion of bits corrupted during transmission?

The measure that indicates the proportion of bits corrupted during transmission is represented by BER, which stands for Bit Error Rate. BER quantifies the number of bit errors divided by the total number of transferred bits during a specified time interval. It is a critical metric in evaluating the performance and reliability of digital communication systems, as it informs you about the likelihood of errors occurring in the transmission of data.

In contrast to this, other options do not reflect the concept of bit corruption in data transmission directly. The rate usually refers to the speed of transmission but does not specifically address errors. Quota typically pertains to limits or allocations, while baud specifically refers to the signaling speed in related to the number of signal changes per second, which can be distinct from actual data error rates. Thus, BER is the correct term to use when discussing the proportion of corrupted bits during data transmission.