The correct answer is D) analog values. In process control, continuously variable values that change without distinct increments, such as temperature, pressure, or level, are correctly referred to as analog values. Analog values are continuous in nature and can take on any value within a certain range, unlike digital values, which are discrete and can only take on specific, distinct values. The other answer choices are incorrect because: A) binary values refer to digital values that can only take on two states (0 or 1), B) "bumpless" is not a recognized term in this context, and C) digital values are discrete, not continuously variable.