To illustrate the interaction of runtime building blocks, the techniques most suitable are Activity diagrams, Sequence diagrams, State diagrams, and Flowcharts. Activity diagrams depict the workflow from one activity to another, providing a clear visualization of sequence and conditions for coordination. Sequence diagrams detail how objects operate with one another and in what sequence, making them ideal for dynamic behavior. State diagrams describe the state changes of system entities, showing interactions as transitions between states. Flowcharts are effective in visualizing the sequence of steps and their interactions in the process. Other options such as Class diagrams focus on static structure, and depictions of screen flows, tabular descriptions, and numbered lists do not provide sufficient detail to illustrate interactions dynamically.