How many 'ml' of perhydrol is required to produce sufficient oxygen which can be used to completely convert 2 lit of $SO_2$ gas to $SO_3$ gas?

Question

\[\begin {array} {1 1} (1)\;10\;ml & \quad (2)\;5\;ml \\ (3)\;20\;ml & \quad (4)\;30\;ml \end {array}\]