Sun, Penumbra, and Corona Consultants, LLP has been contacted by a client in Paris that requested immediate help identifying a fix for a problem in customer data privacy. Which of the following best describes how the costs for the following activity relate to the decision of whether or not to accept this consulting engagement? The firm's annual membership in the American Consultants Society is due next month and is $400 per staff member. O Relevant outlay cost o Irrelevant sunk cost O Relevant opportunity cost o Irrelevant outlay cost