Variance Test is probably the most helpful tool to figure out the correct answer choice of the Evaluate Argument questions.
Stimulus: The management decided to buy A instead of B. A has simpler, more reliable processors, and its average operational span is substantially longer.
Goal: To reduce the maintenance costs.
We are looking for a question that – depending on the answer to the question – helps identify whether buying A instead of B will reduce the maintenance costs. Let’s begin with the correct answer choice because analyzing it with the Variance Test will display why the other choices are wrong.
B. Whether A has higher energy efficiency than B has.
Let’s first answer
YES, A has higher energy efficiency than B has. Indeed, electricity is one of the important maintenance costs of both A and B. If A consumes less electricity than B, then A surely reduces maintenance costs.
Let’s now say
NO, A doesn’t have higher energy efficiency than B has. In this case, A has no advantage over B regarding the maintenance costs. We surely know that A has more reliable processors and longer operational span. However, those are not part of the maintenance costs.
As we can see, opposite answers to B produce different effects on the feasibility goal of the management. Thus B is the correct answer choice.
A. Whether FMP processors’ operational span is significantly longer than that of new models of existing technology.
We already know that information from the stimulus, so it doesn’t help us evaluate the decision of the management.
C. Whether mainframe computer manufacturers still produce and market servers that are based on the older technology as well.
This question doesn’t help us evaluate the decision of the management. The stem already says that there is such a technology.
D. Whether the bank's management intends to purchase more mainframe servers next year, in order to expand its capabilities.
Even if they purchase B for the next year, it doesn’t clarify whether buying A instead of B will reduce the maintenance costs now.
E. Whether other banks in its market recently upgraded their computing systems.
This piece of information is irrelevant to evaluate the feasibility of the management's goal.
Hence
B _________________