A centrosome is a semi-conservative organelle that is not bound by any membrane.
It helps with the generation of spindle fibres during cell division.
Lysozyme is bound by a single-layered unit membrane.
Lysozyme contains the hydrolytic enzyme which is responsible for digesting the cellular components.
Mesosome is a cell organelle which is bound by a double-layered membrane because it is produced due to infolding of the plasma membrane.
The nucleus contains a double-layered nuclear membrane which protects the internal genetic material inside the nucleus.
Hence, the correct answer is option (B).