Based on this information, what is Twinkle's phenotype for the leg color trait?

 - white legs
 - yellow legs
Twinkle's genotype for the leg color gene is LL. Twinkle's genotype of LL has only L allelles. The L allele is for white legs. So, Twinkle's phenotype for the leg color trait must be white legs.
To check this answer, consider whether Twinkle's alleles are dominant or recessive. The allele for yellow legs (l) is recessive to the allele for white legs (L). This means L is a dominant allele, and l is a recessive allele.
Twinkle's genotype of LL has two dominant alleles. An organism with at least one dominant allele for a gene will have the dominant allele's version of the trait. So, Twinkle's phenotype for the leg color trait must be white legs.