Based on this information, what is Marina's phenotype for the tail spots trait?

 - a spotted tail
 - an unspotted tail
Marina's genotype for the tail spots gene is ii. Marina's genotype of ii has only i alleles. The i allele is for an unspotted tail. So, Marina's phenotype for the tail spots trait must be an unspotted tail.
To check this answer, consider whether Marina's alleles are dominant or recessive. The allele for a spotted tail (I) is dominant over the allele for an unspotted tail (i). This means I is a dominant allele, and i is a recessive allele.
Marina's genotype of ii has only recessive alleles. An organism with only recessive alleles for a gene will have the recessive allele's version of the trait. So, Marina's phenotype for the tail spots trait must be an unspotted tail.