Answer:
The correct option is C) crossing over and independent assortment
Step-by-step explanation:
Crossing over and independent assortment can be described as the two essential phenomena of meiosis which brings genetic variations. During crossing over, the exchange of DNA segments between homologous chromosomes takes place. Independent assortment allows the chromosomes to assort independently into gametes hence bringing about the different genetic combinations. Hence, the correct option is C.
Other options, like option A, is false because chromosome inactivation will result in an abnormality.