Which of the following genotypes could be described as heterozygous

Heterozygous genotypes are the ones that are represented one capital and one small letter. Homozygous dominant and recessive are represented by either both capital or small letters. Ex: tall people are dominant, let's say, so TT is dominant and tt is recessive so tt would be short. People are heterozygous reveal their dominant genotype so Tt would also be tall