Which is wrong below as described for directly undoing DNA damages repair.（ ）

A、Converting altered nucleotide back to original form.
B、There is no any DNA synthesis
C、Pyrimidine dimer caused by UV can be repaired by directly undoing DNA damage repair process in human cells.
D、O6-methylguanine methyltransferase can directly remove O6 alkylations on guanine residues by directly undoing DNA damage repair.