You can use combo like

IR = 200
Business Adm = 100
gender studies or Environmental Sci = 100
criminology or philosophy or international law(It is sister subject to IR) = 100
Journalism or Sociology = 100

go through the syllabus and Past papers to know if you can handle a subject or not...ever since syllabus is revised the social science students got an edge on others so you may try these subjects as these are opinion based subjects and you may get away easily if you are observant / expressive enough.