British National and US Citizen

I have been working on college apps recently and have come across a slight predicament with commonapp. The citizenship area offers a section for dual citizenship and as a British National and a US Citizen I am slightly confused on if I say I am a dual citizen although a British National does not have all the same rights as a British Citizen, has a British Passport and I have an American passport too. Is this even necessary or am I overthinking it?

You are overthinking it. The Common App does not distinguish, so select UK and call it a day.

I would only state US citizen. As you know, you are not a British citizen.

ok thanks for your help @Sybylla and @skieurope

US citizenship is the one that they will care about for universities in the US.

US Citizen is the most important for your application - that puts you in the domestic applicant pool instead of the international applicant pool which will make a big difference in some colleges.