Which Built at has a Date of 1946, and a 1947 Nos of 3556/7?
CREATE TABLE table_43559 (
    "1946 Nos" text,
    "1947 Nos" text,
    "Date" real,
    "Built at" text,
    "LMS Nos" text,
    "BR Nos" text
)
SELECT "Built at" FROM table_43559 WHERE "Date" = '1946' AND "1947 Nos" = '3556/7'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: Which Built at has a Date of 1946, and a 1947 Nos of 3556/7? ### Input: CREATE TABLE table_43559 (
    "1946 Nos" text,
    "1947 Nos" text,
    "Date" real,
    "Built at" text,
    "LMS Nos" text,
    "BR Nos" text
) ### Response: SELECT "Built at" FROM table_43559 WHERE "Date" = '1946' AND "1947 Nos" = '3556/7'