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.
1467 Mashona
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, "Mashona" measures between 89.160 and 104.119 kilometers in diameter and its surface has an albedo between 0.05 and 0.083. The "Collaborative Asteroid Lightcurve Link" assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 107.54 kilometers based on an absolute magnitude of 8.57. Among nearly half a million asteroids, "Mashona" belongs to the 200 largest body's.