Answer:
The correct answer is - incomplete dominance.
Step-by-step explanation:
In the betta fish, there are different types of colors found in the fishes depends on the alleles present in their gene which follows incomplete dominance. Incomplete dominance is an inheritance pattern where a dominant allele does not mask completely and produce a blend of both alleles if present in heterozygous condition.
In the question, It is stated that when a cross between RED fish (GG) and a YELLOW fish (gg) produce orange color fish as offspring (Gg) which is a mix or blend of both alleles Red (dominant) and yellow (recessive).