i sense your best bet it to present yourself as someone with a solid skills set that is easily transferable to a number of policy domains. they may ask your preference, in which case, you can tell them. i dont think they are looking for someone who comes across as knowing what the policy should be. i work in a health policy institute and know that there is no single mindset in any policy, and that often there is great disagreement, both between and within stakeholders. the more you come across as flexible and aware of what constitutes a good policy development process, the better, I sense. the more you come across as knowing what the policy should be, the worse, i sense. but I dont know anything about this program.