Explaining that the models are complementation to each other is a technique that helps to resolve the conflict by showing the benefits and limitations of each model, and how they can be used together to provide a more complete and accurate representation of the requirements1. Explaining that the models are complementation to each other can help the BA to satisfy both stakeholders, who may have different preferences or perspectives on how to describe the requirements. This technique can also enhance the quality and clarity of the requirements, as different models can capture different aspects or levels of detail of the requirements2. The other options are not appropriate techniques that the BA should use to resolve the conflict, as they may create or exacerbate issues, gaps, or inconsistencies in the requirements. Allowing both stakeholders to work on the models independently may result in duplication, contradiction, or misalignment of the requirements. Introducing a third model type may confuse or frustrate the stakeholders, who may not be familiar or comfortable with the new model. Suggesting a fusion model may not be feasible or effective, as different models may have different notations, semantics, or purposes. Reference:
1: How to Resolve Conflicts Between Stakeholders Over Requirements Models
2: Why Use Multiple Models to Describe Requirements?