DNA damage can also occur in the form of broken bonds as in the sugar-phosphate backbone of DNA. This type of DNA damage can cause deletion mutations if pieces of DNA break away from the molecule. When those pieces rejoin a different molecule of DNA, what type of mutation has occurred?

A)Messenger Mutation
B)Mechanical Mutation
C)Translocation Mutation
D)Relocation Mutation

i think its B)Mechanical Mutation

Explanation: Because Sometimes, radiation damages a single base on one strand of DNA. This can occur chemically when a hydroxyl (OH-) free radical reacts with a hydrogen atom and forms hydrogen peroxide (H2O2). It is fairly easy to repair damage like this if the complementary (or opposite) strand is undamaged. This is because the DNA sequence on the complementary strand can serve as a template during DNA replication.  

In this case, the cell uses a mechanism called Base Excision Repair (BER). This is the process of cutting out and replacing a single nucleotide.