The most appropriate research question for the team working with the wind turbine would be:
Which angle converts the largest percentage of kinetic energy from the wind into kinetic energy of the turbine?
However, it's important to clarify that in wind turbine terminology, we would typically discuss the conversion of kinetic energy from the wind into mechanical energy (rotational energy) of the turbine, rather than potential energy. Thus, the best phrasing considering technical accuracy might be:
Which angle converts the largest percentage of kinetic energy from the wind into mechanical energy of the turbine?
If you need to choose from the options provided, I would recommend the one about kinetic energy, as potential energy in this context is not applicable.