Final answer:
The correct answer is Expert judgment, as it is a tool or technique used in developing a project charter. The project charter itself, business case, and contracts are documents associated with project management but are not tools or techniques.
Step-by-step explanation:
The question is asking to identify which option is a tool or technique used in the process of developing a project charter during project initiation. According to the Project Management Institute (PMI), the tools and techniques for the Develop Project Charter process include expert judgment, data gathering, decision-making, data representation, and meetings.
Therefore, the correct answer is Expert judgment. It is important to note that while the project charter, business case, and contract are important documents or inputs in project management, they are not considered tools or techniques themselves. The project charter is the output of the Develop Project Charter process, the business case is an input, and contracts are usually inputs to other processes in project procurement management.