Final answer:
The correct answer to the question is D) B & C, meaning a differential analysis can be used to compare any set of alternatives and is more comprehensible with a consistent frame of reference.
Step-by-step explanation:
A differential analysis can be used to compare any set of alternatives and is easier to comprehend if a consistent frame of reference is employed. This means that the correct answers to the question are options B and C, which when combined indicates that choice D) B & C is the correct one. In differential analysis, keeping a consistent frame of reference is similar to the concept of ceteris paribus in economics, which allows examining the effect of one variable while holding others constant. This approach facilitates the understanding and comparison of the implications of different choices or scenarios.