Answer:
Rr only
Explanation:
As you saw in the question above, in a population of snapdragons, the "R" allele is the dominant allele and represents the red seeds, while the "r" allele is recessive and represents the white seeds.
If there was a cross between a snapdragon with the "RR" alleles and a snapdragons with the "rr" alleles, the entire offspring would receive an allele from each parent and as a result, the entire offspring would have the "Rr" alleles and be red seeds, since recessive alleles are only expressed when paired with other recessive alleles.
You can see the punnet square for this intersection in the figure below.
