Correct Option: D

Commonly used methods for the covalent immobilisation of enzymes includes activation of Sepharose by cyanogen bromide. Conditions are chosen to minimise the formation of the inert carbamate. Glutaraldehyde is used to cross-link enzymes or link them to supports. It usually consists of an equilibrium mixture of monomer and oligomers. The product of the condensation of enzyme and glutaraldehyde may be stabilised against dissociation by reduction with sodium borohydride.