What is the end result of natural selection?

a.
increased number of offspring of a given phenotype that survive
b.
changes in the frequency of alleles in a population
c.
fossil formation through extinction
d.
environmental changes of a habitat

Pls me i need this ! each cell has genes activated depending on it's job and what kind of cell it is. it is the presence of that causes the repressor protein to fall off and unblock the gene on the lac operon. if a gene is turned on then it is being an additional circular chromosome found in some bacteria that is used in genetic engineering.