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

Question

Genes and Loci | BioNinja

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

Answer 1

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