3. Which of the following can lead to transition mutations? (A) A small insertion or deletion. (B) Incorporation of a base analog that exhibits different base-pairing properties from the base it replaces. (C) Chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base. (D) Incorporation of a base analog that exhibits different base-pairing properties from the base it replaces and chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base.