Answer:
Co-dominance
Explanation:
Considering the allele for red pigment as CR and that for a white pigment CW, a pink flower will equally express both the pigments in its phenotype and will thus have a genotype of CR CW.
Crossing CR CW × CR CW you'll get,
25% CR CR - red flowers
50% CR CW - pink flowers
25% CW CW - white flowers