In polythionic acid, \({H_2S_xO_6} \) (\( x = 3 \) to \( 5 \)) the oxidation state(s) of sulphur is/are:
\( +5 \) only
\( +6 \) only
\( 0 \) and \( +5 \) only
\( +3 \) and \( +5 \) only