A cross between t

Tt and Tt are the genotype of both the parents.

Tall plants can have the genotype as TT or Tt while dwarf plants can have the genotype as tt only.

In 1^st case where the parents are having genotype as TT and Tt

All plant progeny are tall.

Therefore 1^st case is not the answer as it does not generate any dwarf plants.

In 2^nd case where the parents are having genotype as Tt and Tt

3/4^th of the F₂ plants are tall and 1/4^th of the F₂plants are dwarf.

Therefore 2^nd case is the answer as 1/4^th of the progeny are dwarf when two tall plants are crossed.

In 3^rd case where the parents are having genotype as TT and TT

All the progeny are tall.

Therefore 3^rdcase is not the answer as the cross does not generate any dwarf plants.

In the 4^th casewhere plants are having genotype as Tt and tt ; one of them has the phenotype to be dwarf . But according to the question the cross is done between two tall plants , hence the given case is not the answer.