If your Simulink model has coninuous signal but no continuous states, which solver should be preferred to be used?

When a model has continuous signals but no continuous states (no differential equations requiring integration), a variable-step discrete solver is most efficient. It handles continuous signal propagation without the computational overhead of ODE solvers. Fixed-step solvers (A, B) are less flexible. Variable-step ODE solvers (D) are unnecessary without continuous states.