CREATE TABLE table_75160 ("Region" FLOAT, "Group A" TEXT, "Group B" TEXT, "Group C" TEXT, "Group D" TEXT, "Group E" TEXT, "Group F" TEXT)

What is the group C region with Illinois as group B?
SELECT "Group C" FROM table_75160 WHERE "Group B" = 'illinois'
SELECT "Group C" FROM "table_75160" WHERE "Group B" = 'illinois'