The correct option is D Starch sheath
The monocot stem vascular bundles are surrounded by bundle sheaths made of sclerenchyma. In mature monocot stems, a part of the xylem dissolves and forms a water-filled cavity called the lysigenous cavity. The hypodermis of the monocot stem is made of sclerenchyma. Starch sheath is another name for the endodermis. The endodermis is absent in monocot stems, hence there is no endodermis.