Answer:
Both "D" and "d" allele
Step-by-step explanation:
As per the principle of segregation proposed by mendel, an allele pair can split in to two during cell division in a way such that it can give both of its allele (with in an allele pair) to its offspring.
Thus by that logic anyone with a genotype Dd, can segregate its allele pair to pass both "D" and "d" allele to its offspring.