In reality , it was sand . Sand used to make the finest glass . After the war , the Barcid king had ordered that no glass was to be given to outsiders at any cost . Thus , over the years , glass had become scarce and the process of glass making lost to the world .

OPT:
+ He did n't want anyone to wear glasses .
+ He wanted to punish his subjects and make them go glassless .
+ None of the above choices .
+ He did n't want anyone to compete with his kingdom regarding the glass trade ( Monopoly )
Q: What is the reason the Barcid King ordered no glass was to be given to outsiders ?
He did n't want anyone to compete with his kingdom regarding the glass trade ( Monopoly )