What is the significance of crossing-over, independent assortment, and random fertilization?

What is the significance of crossing-over, independent assortment, and random fertilization?
A) an increase in the number of gametes produced by an individual, thereby increasing the chance that fertilization will occur
B) an increase in the genetic diversity of gametes and zygotes
C) an increase in the number of daughter cells produced by mitosis, thus providing a mechanism for rapidly repairing injured tissues
D) a decrease in the genetic complexity of living systems, making it more likely that a species will survive
E) a decrease in the amount of time it takes to produce gametes