What is not true for an angiospermic embryo sac ?

Two male gametes are discharged within the embryo sac. One of the male gamete fuses with the egg cell and produces the diploid zygote and the other male gamete fuses with the diploid secondary nucleus to form the triploid primary endosperm nucleus.

Embryo sac represent the female gametophyte and therefore it is haploid. The embryo sac develops from the functional megaspore formed inside the ovule. 

The megaspore mother cell undergoes meiosis and forms four megaspores. Out of the four megaspores only one is functional and other 3 degenerates.  This functional megaspore then develops into embryo sac.