The right option is; A. genes
Genes is the source of the instructions from which all of the proteins are made.
Genes are the subunits of DNA (deoxyribonucleic acid) that contains a specific set of instructions, usually coding for a certain protein or for a certain function. There are about 50,000 and 100,000 genes with each containing hundreds of thousands of chemical bases. In humans, every individual has two copies of each gene, one inherited from each parent. A gene can exist in many alternative forms known as alleles which may be dominant (strong) allele, or recessive (weak) allele.
