Answer:
The correct answer would be option D. T or t.
It can be explained with the help of the law of segregation.
This law states that alleles for each gene are randomly segregated into the gametes such that each gamete carries only a single copy of each allele.
Hence, if a parent cell contains T and t alleles so, T and t will randomly segregate into pollen grains (gametes).
It will result in the formation of two types of pollen grains or gametes each having an equal chance of inheriting T as well as t.
So, we can say that pollen grain produced by the plant (Tt) can carry either T or t in it.