How does natural selection work with regards to genes and what is passed to the next generation?

Genes and Loci | BioNinja

a
Those with the most favorable combination of genes survive and pass their DNA to the next generation.
b
Those with the most favorable combination of genes die off not allowing their DNA to be passed on to the next generation.
c
Natural selection allows genes to mutate changing the species of an organism.
d
Those with the least favorable combination of genes survive and pass their DNA to the next generation.

a. Those with the most favorable combination of genes survive and pass their DNA to the next generation.

Natural selection works by selecting for individuals with traits that give them a reproductive advantage in their specific environment. These advantageous traits are often coded for by specific genes, and individuals who possess these favorable genes are more likely to survive, reproduce, and pass on their genes to the next generation. Over time, the frequency of these advantageous genes in the population increases, leading to evolutionary change. Conversely, individuals with less favorable combinations of genes may be less likely to survive and reproduce, leading to those genes being passed on to fewer offspring.