What was the yield of the K-4 explosion?
CREATE TABLE table_19623 (
    "Explosion" text,
    "Location" text,
    "Date" text,
    "Yield (approximate)" text,
    "Altitude (km)" text,
    "Nation of Origin" text
)
SELECT "Yield (approximate)" FROM table_19623 WHERE "Explosion" = 'K-4'
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: What was the yield of the K-4 explosion? ### Input: CREATE TABLE table_19623 (
    "Explosion" text,
    "Location" text,
    "Date" text,
    "Yield (approximate)" text,
    "Altitude (km)" text,
    "Nation of Origin" text
) ### Response: SELECT "Yield (approximate)" FROM table_19623 WHERE "Explosion" = 'K-4'