Which of the following structures in the life cycle of a pine are haploid?

A)pollen grains, megaspore, female gametophyte, egg nucleus
B)new sporophyte, pollen cone, pollen grains, microsporocytes
C)mature sporophyte, ovulate cone, pollen cone, female gametophyte
D)megasporocyte, megasporangium, megaspore, female gametophyte