fixed null and string problems with answers
fixed null and string problems with answers

donkey-hotei/edurange,edurange/edurange-server,edurange/edurange,donkey-hotei/edurange,edurange/edurange,donkey-hotei/edurange,donkey-hotei/edurange,edurange/edurange-server,edurange/edurange,edurange/edurange-server,edurange/edurange,edurange/edurange-server