Natural selection acts on a variation of populations of living things usually through a specific trait which statement must be true about that trait

Considering the following statements; 
A. The trait is the same for all organisms
B. The trait is resistant to mutations
C. Most forms of the trait have the same impact on survival
D. The trait is passed on genetically to the next generation 
The correct answer is D. 
Genetic variation is essential for natural selection since natural selection can only increase or decrease frequency of alleles that already exist in the population. Genetic variation is caused by mutation and random mating organisms.