In snapdragons, when a plant with red flowers (RR) is crossed with a plant with white flowers (rr), the offspring will inherit one allele from each parent. Since red flowers (R) are incompletely dominant over white flowers (r), the genotype of all the offspring will be Rr.
The phenotype of Rr (incomplete dominance) will result in pink flowers.
Therefore, the correct response is:
All pink.