Answer:
tt
Step-by-step explanation:
Firstly, look at the oldest female shape. It would be a circle since that is female and which circle, would be the oldest one. In line one. Since the circle is white, the gene has not been carried so it must be reccessive.
tt because it is the only allele pair that would give you the gene without obtaining that trait, meaning it is reccessive.
So it would make sense that tt is the choice.