The correct option is D Polygenic inheritance
Polygenic inheritance occurs when one character is controlled by two or more genes. Often the genes are large in number but small in effect. Examples of human polygenic inheritance are height, skin color, eye color and weight.
Codominance is observed when alleles of a gene pair in a heterozygote are fully expressed. This results in offspring with a phenotype that is neither dominant nor recessive. A typical example showing codominance is the ABO blood group system.
A chromosome abnormality, disorder, anomaly, aberration, or mutation is a missing, extra, or irregular portion of chromosomal DNA. It can be from an atypical number of chromosomes or a structural abnormality in one or more chromosomes.