If it is a senior camp, they may want C or even C+, as far as I am aware there is no "camp test" as such, but different branches do things differently, and perhaps yours has a competency test before you can attend?
DC or camp organiser will know.
The only required test for PC Camp is the D+ test. That is really low key and can be done by an accredited instructor during a normal lesson or a rally. Its required for insurance. Some larger branches split camps and have a camp specifically for more experienced / advanced members and might well have a requirement for one of the more advanced tests, but it isn't a national requirement. Check with your DC.