C-type asteroid
The largest unequivocally C-type asteroid is 10 Hygiea, although the SMASS classification places the largest asteroid, 1 Ceres, here as well, because that scheme lacks a G-type.
65 Cybele
Cybele ( minor planet designation: 65 Cybele) is one of the largest asteroids in the Solar System and is located in the outer asteroid belt. It gives its name to the Cybele group of asteroids that orbit outward from the Sun from the 2:1 orbital resonance with Jupiter. The X-type asteroid has a relatively short rotation period of 6.0814 hours. It was discovered by Wilhelm Tempel in 1861, and named after Cybele, the earth goddess.