A strand of DNA in a skin cell contains the bases: A-T-G-C-C-A-T-C-G-G-T-A After the cell is exposed to ultraviolet light, the strand contains the bases: A-T-G-G-C-C-A-T-C-G-G-T-A Which statement describes the result of this exposure?a. A new base has been inserted.b. A base has been deleted.c. One base has been substituted for another.d. There have been no changes in the bases.