As this is an example of codominance ..here both the allele represent their character and the final heterozygous trait obtain will be in betweeen the two i.e pink(RW)

Explanation:

In the given scenario, red (RR) Antirrhinum is crossed with a white (WW) one, and the resulting offspring are pink (RW). This is an example of incomplete dominance.

Incomplete Dominance:
Incomplete dominance occurs when the heterozygous phenotype is an intermediate blend of the two homozygous phenotypes. In this case, the phenotype of the offspring (pink) is a blend of the phenotypes of the two parental plants (red and white).

Genotypes and Phenotypes:
- Red Antirrhinum (RR) has the genotype for red color and displays the red phenotype.
- White Antirrhinum (WW) has the genotype for white color and displays the white phenotype.
- The offspring of the cross (RW) have one allele for red color and one allele for white color, resulting in a blend of the two colors, which is pink.

Explanation of Options:
a) Dominant-Recessive: Dominant-recessive inheritance occurs when one allele (dominant) masks the effect of another allele (recessive). In this scenario, neither the red nor the white allele is completely dominant over the other, as the resulting phenotype is a blend of the two.
b) Incomplete Dominance: As explained above, incomplete dominance is the correct answer because the phenotype of the offspring is an intermediate blend of the phenotypes of the two parents.
c) Hybrid: Hybrid is a term used to describe the offspring resulting from a cross between two different species, varieties, or breeds. While the offspring in this scenario are a result of a cross, the term "hybrid" is not specifically applicable here.
d) Supplementary Genes: Supplementary genes refer to genes that modify the phenotypic expression of other genes. In this scenario, there is no mention of supplementary genes affecting the color expression.

Therefore, the correct answer is option B) Incomplete Dominance.