The correct option is A One fuses with the egg and other fuses with central cell nuclei
In flowering plants, the pollen tube releases the two male gametes into the cytoplasm of the synergid.
One of the male gametes fuses with the egg cell forming the zygote. This is called syngamy.
The other male gamete fuses with the two polar nuclei in the central cell to produce a triploid primary endosperm nucleus (PEN). This is called triple fusion.
Since two types of fusions take place (syngamy and triple fusion), this event is called double fertilisation. It is unique to angiosperms.