Embryo sac is monosporic when it dovelops from

Embryo sac is monosporic when it dovelops from Correct Answer One of the four megaspores of a megaspore mother cell

The embryo sac is monosporic when it develops from one of the four megaspores of a megaspore mother cell.
In monosporic development, the egg apparatus is organized from a group of four nuclei at the micropylar pole of the syncytial embryo sac. These nuclei are derived from the chalazal megaspore of the tetrad.
One cell of the nucellus undergoes meiosis to produce four megaspores. One megaspore survives and undergoes three rounds of the free nuclear division followed by cellularization to produce an embryo sac consisting of 8 nuclei in 7 cells.
At the micropylar end, two peripheral cells develop into synergids (which attract the pollen tube for sperm delivery), and the third cell differentiates into the egg cell.