The correct option is B Mesocarp
Coir is a natural fibre extracted from the husk of coconut and used in products such as floor mats, doormats, brushes, mattresses, etc. Coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. A coconut, and all drupes, have three layers - the exocarp (outer layer), the mesocarp (fleshy middle layer) and the endocarp (hard, woody layer that surrounds the seed). An untouched coconut has three layers. The outermost layer, which is typically smooth with a greenish color, is called as the exocarp. The next layer is the fibrous husk or mesocarp, which ultimately surrounds the hard woody layer called as the endocarp. The endocarp surrounds the seed. Coir of commerce is obtained from mesocarp of coconut.
Therefore, the correct answer is option B.