CREATE TABLE table_26907 ("Codename  ( main article ) " TEXT, "Brand name  ( list ) " TEXT, "Cores" FLOAT, "L3 Cache" TEXT, "Socket" TEXT, "TDP" TEXT, "I/O Bus" TEXT)

What is the i/o bus for the brand name Core i3-21xx?
SELECT "I/O Bus" FROM table_26907 WHERE "Brand name (list)" = 'Core i3-21xx'
SELECT "I/O Bus" FROM "table_26907" WHERE "Brand name (list)" = 'Core i3-21xx'