The answer is probably tt
Well for parent 1 and parent 2 ( 1st parent of 2 ), parent 1 shows T so it forms Tt
Parent 1 and 2 ( 2nd parent of 2 ) ( parent 1 also has T and parent 2 has t ) so it forms Tt
Parent 1 ( 2nd parent of 1 ) and parent 2 has t and parent 1 is normal which forms tt
So that leaves 2nd parent 1 and parent 2