PLEASE HELP Which of the following DNA repair processes accurately restores genetic information only immediately after the DNA has been replicated?

PLEASE HELP

Which of the following DNA repair processes accurately restores genetic information only immediately after the DNA has been replicated? 

(a) Repair of deamination (b) Repair of depurination (c) Mismatch repair (d) Repair of pyrimidine dimers

Which of the following compounds is likely to be the most mutagenic?

(a) One that depurinates DNA. 

(b) One that replaces adenine with guanine during DNA replication

(c) One that nicks the sugar-phosphate backbone

(d) one that causes thymidine dimers

(e) One that crosslink together the two strands of the double helix