CREATE TABLE table_11399 ("Year" FLOAT, "Chassis" CLOB, "Engine ( s ) " CLOB, "Tyres" CLOB, "Points" FLOAT)

What engine was made in 1991?
SELECT "Engine(s)" FROM table_11399 WHERE "Year" = '1991'
SELECT "Engine(s)" FROM "table_11399" WHERE "Year" = '1991'