The correct option is A sclereids
Sclereids are one of the cell types that make up the sclerenchyma. Sclereids come in different shapes and their cell walls are highly thickened by the deposition of lignin. The hard stony nature of the coconut shell is due to the presence of sclereids.
Fibres are long, tapering towards the ends and bulging in the middle.
Collenchyma is an example of a simple permanent living mechanical tissue. The cell wall is made of cellulose, hemicellulose and pectin.
Parenchyma is an example of a simple living tissue. It is the most commonly found tissue in plants.