The allele will be a single letter, while the genotype will be the pair, like you have. For example, number 1 would be:
Dominant: allele= T genotype=TT or Tt
Recessive: allele= t genotype= tt
(T/t is used since the topic is height, for number 2, the letter D will be used (for “detached”)
(Both TT And Tt are genotypes for the dominant height since if a T is evident at all, the gene will be the dominant allele)