What genetic defect is associated with HNPCC (hereditary nonpolyposis colorectal cancer)?

a) MOA: MTX, TMP, Pyrimethamine
b) Genetic defect: HNPCC (hereditary nonpolyposis colorectal cancer)
c) Anti-U1 RNP antibodies
d) Scurvy, Osteogenesis Imperfecta, Ehlers-Danlos, Menkes