Correct option is A
According to given information:
I. Kirti is not taller than Tia and Ravi.
Tia/Ravi > Kirti
Statement I alone not sufficient.
II. Ravi is taller than Kirti but not as tall as Tia.
Tia > Ravi > Kirti
Statement II alone not sufficient.
III. Pragnesh is taller than Deepa and Nilesh but not as tall as Tia.
Tia> Pragnesh > Deepa/Nilesh
Statement III alone not sufficient.
Statement II and III:
Tia > Pragnesh / Ravi / Kirti > Deepa /Nilesh / Ravi / Kirti
So, Tia is tallest.
Statement only II and III are sufficient.
Thus, the correct answer is (a).