Answer:
A - the cell would have new genetic variation not present in other cells
Step-by-step explanation:
Option B is incorrect because the mutation is viable and gametes/cells missing chromosomes are typically not viable
Option C is incorrect because the mutation that is viable will not have an effect on future proofreading errors --> this is independent of the process whether or not the mutation is there in the first place
Option D is incorrect because mutations from the environment are random