This is the reasoning used to reach a decision based on a set of assumptions

Logic is the right answer.

Explanation:

Logic is a term which can be explained as reasoning conducted or evaluated following strict laws of validity. In this way, logical can be something that comes from explicit reasoning. Logic plays a significant role in the process of effective thinking. The essential building blocks in logical reasoning are the inferences. Therefore, logic is the reasoning used to relinquish a choice on the basis of a set of theories, or it may be explained as the science of argumentation, thinking, proof or inference.

the telephone is the answer

you probably know the answer. stop asking stupid questions and making me waste my time. j.k. ; )   b.t.w. what are three ratios equivalent to 5 : 11? thx