Hello,

First of all for appearing in SSC CGL exam, the eligibility criteria is only passed graduation in any discipline from a recognized university, only in case of following posts the criteria is subjects specific;

Assistant Audit Officer/Assistant Account Officer; essential qualification is pass bachelor's degree in any discipline from a recognized university while the desirable qualification is chartered accountant or cost & management accountant or company secretary or masters in commerce or masters in business studies /masters in business administration (finance) or masters in business economics.

Junior Statistical Officer; Bachelor's degree in any subject with 60% marks in  maths at 10+2 level, or bachelor's degree in any subject with statistics as one of the subject from a recognized university.

Statistical Investigator Grade-II; Bachelor's degree in any subject with statistics  as one of the subject in all the years of graduation from a recognized university.

If you have any other preference than ITO, because the above mentioned posts are very good options, then as per the eligibility criteria you may can choose such as havings maths/statistics as subject or even major with these subjects.