The correct answer is: B) stabilizing selection
Stabilizing selection is a type of natural selection in which the population mean (non-extreme trait value) is favored over extreme values. It favors the intermediate variants such as heterozygous phenotype (more than both homozygous). This is the most common type of selection, because most traits change little over time (not by favoring extreme traits).
You don't have any listed but here they are:
Protein - Amino Acid
Carbohydrate - monosaccharide
Nucleic Acid - nucleotide
Lipid - triglyceride
