Ans.
Mistakes during DNA replication, such as addition of an incorrect nucleotide base in daughter strand or breaks in daughter strand that leads to change in nucleotide sequence of DNA, are known as DNA replication errors.
The enzyme DNA ligase repairs the breaks or irregularities in the DNA molecules, such as joining of Okajaki fragments. Therefore, defects in DNA ligase that take apart chunks of DNA would cause an error during DNA replication.
Thus, the correct answer is 'option B).'