A compound soluble in conc. `H_(2)SO_(4)`. It does not decolourise bromine in `C Cl_(4)` but oxidised by chromic anhydride in aqueous `H_(2)SO_(4)` within two seconds, turning organs solution to blue, green and then opaque. The original compound is `:`
A. an alkene
B. a primary alcohol
C. a tertiary alcohol
D. an ether