What mutations would likely be most dangerous to a cell?

Frameshift mutation caused by the deletion of one nucleotide.

Explanation:

The mutation is a random process taking place in the cell which causes alteration or change in the sequence of the DNA. The mutation auld prove beneficial to organisms like in the case of natural adaptation or it could be harmful to the cell.

The mutation which proves dangerous to the cell is caused by the deletion of one nucleotide from the sequence of the DNA as depletion of one nucleotide changes the frame of the sequence of the protein during translation.

Thus, Frameshift mutation caused by the deletion of one nucleotide is the correct answer.