Answer:
Epistasis
Step-by-step explanation:
In epistasis or epistatic gene interaction, alleles in a particular locus interact with allele at another locus to bring about a phenotype.
Most of the time, the interaction usually comes in the form of suppression or modification of an allele on a particular locus by an allele in another locus.
In this case, gene A and B controls the phenotypic expression of flower colours in common daisy. The presence of either or both makes the flowers of common daisy to be colourful while the absence of both makes the flowers to be white phenotypically.
The presence of either or both of A and B modify the expression of the gene that is responsible for flower colour. This is a good illustration of epistatic gene interaction.