Answer:
a. a higher-than-normal rate of DNA synthesis errors
Step-by-step explanation:
A mutation that knocked out the proofreading ability of DNA polymerase would result in a higher than normal rate of DNA synthesis errors.
The synthesis of DNA or DNA replication usually comes with error which are fixed by the polymerase enzyme. The enzyme proofreads the base sequence and ensures that the correct nucleotide bases which are complementary to the parent strand are added to the new, elongating strand each time.
If a mutation occur to the DNA polymerase enzyme and it losts the ability to proofread and fix errors, it means a higher-than-normal error rate will occur at the end of replication.
It is just like authors publishing their works directly without the input of editors.
The correct option is a.