Which of the following is MOST important for an IS auditor to look for in a project feasibility study?

While a cost-benefit analysis (benefits exceeding investment) is part of feasibility, it's a financial assessment; verifying that the benefits themselves are achievable (option C) is a broader, more fundamental aspect of feasibility.

An assessment of security control effectiveness is important for project security and risk management, but it's a specific aspect, not the overarching "most important" element of overall project feasibility.

The core purpose of a feasibility study is to determine if a proposed project is viable and practical, particularly concerning whether its intended outcomes and benefits can actually be realized. An IS auditor needs to ensure that the project's objectives are clearly defined, measurable, and realistically attainable given the available resources, technology, and organizational context, as unrealized benefits undermine the project's justification.

Assessing whether requirements will be fully met is critical for project success, but it's a component of achieving the expected benefits. If requirements are met but don't lead to the desired benefits, the project is still not feasible in terms of value.