You must show you have attempted the question, it is a
Forum Rule. In addition, please format your formulae properly and avoid chat room abbreviations.
From part a), you should have worked out how many electrons are involved in the oxidation of sulfite.
The stoichiometry of the reaction (ratio of metal to sulfite) is given (or can be deduced) from the opening of the question.
If you combine these pieces of information, you should be able to find the answer. Post your attempt and we'll take it from there.