Final answer:
A throw away prototype is most appropriate when there are gaps in understanding, difficulties in envisioning the system from requirements, or uncertainties in the specifications. It is used to refine these elements through testing and iteration, and thus the answer is 'All of them mentioned'.
Step-by-step explanation:
A throw away prototype is most appropriate when users and developers need to bridge gaps in understanding the requirements, envision the system, or deal with uncertainty in the specifications. When complexity or ambiguity is present in requirements, a prototype serves to clarify and refine those requirements through a process of iteration and testing. In such scenarios, prototypes are crucial in evaluating different aspects of the design. They help to test if the design meets the necessary constraints and performs optimally according to the established criteria. This is especially important when there is a risk of poor design decisions early in the process, which could lead to an unsuccessful final product that does not meet customer needs.
Therefore, the correct answer here is C. All of them mentioned, as each listed scenario justifies the creation of a throw away prototype. These prototypes can be used to ensure that the users can judge whether the requirements will enable necessary business processes, help in cases where the stakeholders have difficulty envisioning the system from the requirements, and address any gaps, uncertainty, ambiguity, incompleteness, or vagueness in the requirements.