Answer: The correct answer is C) Although the F1 generation will all show the dominant trait, the offspring will all be heterozygous and increase chances of future variation.
According to Mendelian inheritance, true breeding parents ( which are homozygous dominant and homozygous recessive) for dominant and recessive allele will always result into offsprings with heterozygous dominant genotype.
As per the question, genotype of P ( parental ) generation is AA and aa. When they are crossed together, they result into Aa offsprings, which all exhibit dominant character/ phenotype. These offsprings will increase the chances of future variation.