Please answer my question

Dear student,
Please find below the answer:

The correct option is (a).

F1 generation

	T	T
t	Tt	Tt
t	Tt	Tt

F1 generation would have all tall plants. F2 generation on selfing plants in the F1 generation.

	T	t
T	TT	Tt
t	Tt	tt

We would get 3 tall and one dwarf plant in the F2 generation.

Since the generation is not mentioned in your question, please go with answer that matches F1 generation.

Hope this clears your doubt.
Regards.