Hello,if your concepts are strong you should join aakash institute Kolkata and if your concepts needs work you should join goal institute because for droppers aakash emphasis more on problem solving rather than long theory concept builder classes which makes you efficient during test but if you want to strengthen your base goal would be better option. Whatever you join don't forget to join any national test series like of Allen and resonance because test series and their self analysis matters the most . All the best.