The provided question lack the essential part which is required to answer the question, however the correct part is attached with with the question as image.
Answer:
From the provided punnett square it is clear that the genotype of parents are Rr for each. On this basis offspring which is maria that can be either RR, Rr, or rr. Maria have chances to get RR= 25%.
There can be no 100 surety of the phenotype of maria as there is 25% chances of rr and 75% of ability of tongue rolling.
to get Rr=50% and rr = 25%
