Casparian strips are present in ......................... of the root.

Casparian strips are modifications of the cell wall bearing ring-like structure found in the endodermis of the vascular plant roots. The endodermis is a layer separating the cortex from the stele. Thickening in the endodermis consisting of cutin, lignin, and suberin leads to the formation of Casparian strips.

Hence, option D. i.e., Endodermis, is the correct answer.