Borax: \\\\(Na_{2} B_{4} O_{7} .10H_{2} O \\\\)Razorite: \\\\(Na_{2} B_{4} O_{7} .4H_{2} O \\\\)Bauxite: \\\\(Al_{2} O_{3} .2H_{2} O \\\\)Colemanite: \\\\(Ca_{2} B_{6} O_{11} .5H_{2} O \\\\)So, the correct option is 'C'.