If crossing over and independent assortment ceased to occur,
a. genetic variation would decline rapidly, with sperm or ova having the same alleles.
b. sperm will always have the same alleles, but ova will always have different alleles.
c. ova will always have the same alleles, but sperm will always have different alleles.
d. sperm or ova would alternate between the types of alleles they will contain.

Genetic variation would decline rapidly, with sperm or ova having the same alleles.

Explanation:

Crossing over is the exchange of genetic material between the chromatids of homologous chromosomes. It results in the formation of recombinant chromatids that have new combinations of maternal and paternal alleles. The gametes with recombinant alleles impart genetic variations to the progeny.

Likewise, an independent assortment of homologous chromosomes to the opposite poles during anaphase I of meiosis I result in the packing of alleles of a gene independent of that of the other gene. Independent assortment produces some gametes with new gene combinations and the other with parental gene combinations.

If crossing over and independent assortment cease to occur, male and female gametes will have the same alleles due to the absence of any source of recombination and the genetic variation in the progeny would be reduced.  

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.

the answer to your question is sperm