Answer:a). mutated DNA strand
Explanation: Mutation is a permanent alteration or change in the nucleotide sequence of a DNA. When one or more wrong nucleotides are added to a growing strand of DNA during replication, the base pairs involved are said to be mismatched. These mismatches result in a mutated DNA strand instead of a complementary DNA strand. Normally, new DNA strands are complementary to the template strand in the sense that they are not the same in base composition and sequence rather, wherever adenine is found in the template strand, thymine occurs in the new strand and wherever guanine occurs in the template strand, cytosine occurs in the new strand.