Answer A is incorrect because the WBS hierarchy does not prevent duplication by itself. Answer C is incorrect because a WBS is focused on deliverables and components or work packages and not on tasks. Answer D is incorrect because a WBS can be sized appropriately to the project size with as many levels as necessary.

Answer A is tempting because it is true by definition, but Answer B is correct because it properly answers the question, in that these techniques do not take into account resource pool constraints. Answer C is incorrect because it provides possible early and late start and finish dates, but not the actual schedules. Answer D is incorrect because none of the the three are simulation techniques. 

Richard is using an estimate based on a project very similar to to his own with staff he will be using.  Answer A is incorrect because perametric modeling involves using a mathematical model to predict costs, such as dollars per line of code. Answer C is incorrect, although close; if the development project is a common item, such as putting down new flooring, a rule -of-thumb measurement can be used, although it is less accurate. Answer D is incorrect because it is not a form of estimating, but a type of pricing.

The approval by the Architecture Review Board is a milestone you want to include in activity sequencing so that you can ensure the requirements for meeting the review board's approval are met.  Answer A is tempting because the question references phase-end activities; however, it is not an example of gatekeeping because the project is not being authorized to continue based only on the architecture review.Gatekeeping often involves the review of other factors as well. Answer C is incorect because the requirement of a review board approval does not afect scope. Answer D is incorrect because project integration planning involves project plan development, execution, and integrated change control, which are not related to a review board.

Answer A is tempting because the problem focuses on changes. However, because we are talking about the elaboration of the product's characteristics, we are talking about scope changes, and therefore Answer B is the best answer. Answer C is also tempting because it is difficult to more forward on a project until the scope is clearly defined (especially in systems development projects), but with products and certain types of web development, scope changes can be frequent, and a formal scope management plan is needed. Answer D is true from a project perspective, but does not addres the scope issues.

Life Cycle costing includes the costs from each phase of the project life cycle when the total investment costs are calculated. Answer A is incorrect because an opportunity cost is the difference between a chosen investment and the one that is passed up. Answer B is incorrect because sunk costs are costs that have been incurred and cannot be reversed. Answer C is incorrect because net present value (NPV) is the present value of cash inflows(benifits) minus the present value of cash outflows (costs).