I think it is that the cytoplam divides
If an A (Adenine) were swapped for a T (Thymine) it will lead to A TRANSVERSION TYPE OF POINT MUTATION.
Replacement of an A with a T is a transversion type of point mutation because in transversion the purine is replaced with a pyrimidine. Since in this case only one nucleotide is replaced, it is a point mutation.
The correct choice is B. The enzyme binds to the substrate. The other choices are incorrect.
The sentence probably saying about polyploid
Polyploid is when the cell duplicates a complete set of chromosome. This will result in one extra chromosome for each kind which makes them triploid, tetraploid or more. The polyploid organism will more likely to die. In the animal, the extra chromosome will cause sexual imbalance and can make it infertile.