Answer:
D) crossing-over.
Step-by-step explanation:
Crossing over is the biological phenomenon that occurs during cell division and involves the exchange of pieces of the honorary chromatids.
During crossing over, some parts of the chromatids break and some pieces are released. When this occurs, the chromatids exchange these pieces between them, resulting in new gene sequences on the chromosome (which is totally new for that organism).
This phenomenon allows that there are several genes combined in different ways to those that the cell originally presented.