On heating an inorganic salt 'X' with conc.Hâ‚‚SOâ‚„ results in evolution of reddish brown fumes which on addition of MnOâ‚‚, the fumes get intensifies. The fumes turns starch paper yellow. X is
A. Nitrate salt
B. Bromide salt
C. Fluoride salt
D. Sulphate salt