The correct answer is B. bits.
Resolution is the number of discrete steps that can be represented in a measurement. In digital systems, resolution is often expressed in bits. A bit is the smallest unit of information in a computer, and it can be either a 0 or a 1. The more bits that are used to represent a measurement, the higher the resolution. For example, a 1-bit measurement can only have two values (0 or 1), while a 2-bit measurement can have four values (00, 01, 10, and 11).
The other options are incorrect because they are not units of information. A byte is a group of 8 bits, a word is a group of bits that is larger than a byte, and a nibble is a group of 4 bits.
In conclusion, resolution is expressed in bits. The more bits that are used to represent a measurement, the higher the resolution.