The reaction occurs only at extremely high temperatures.
O Fusion
O Fission

fission

Explanation:

fusion

To make fusion happen, the atoms of hydrogen must be heated to very high temperatures (100 million degrees) so they are ionized (forming a plasma) and have sufficient energy to fuse, and then be held together i.e. confined, long enough for fusion to occur. The sun and stars do this by gravity.

fission doesn't require high temperature

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.