The ability to taste PTC (phenylthiocarbamide) is determined by a simple Mendelian trait where the tasting ability is dominant over the non-tasting trait. In this case:
- TT (homozygous dominant) and Tt (heterozygous) individuals can taste PTC.
- tt (homozygous recessive) individuals cannot taste PTC.
Therefore, the correct answer is TT and Tt.