Find the type code of the most frequently used policy.
CREATE TABLE claims_processing (
    claim_processing_id number,
    claim_id number,
    claim_outcome_code text,
    claim_stage_id number,
    staff_id number
)

CREATE TABLE customers (
    customer_id number,
    customer_details text
)

CREATE TABLE claims_processing_stages (
    claim_stage_id number,
    next_claim_stage_id number,
    claim_status_name text,
    claim_status_description text
)

CREATE TABLE claims_documents (
    claim_id number,
    document_type_code text,
    created_by_staff_id number,
    created_date number
)

CREATE TABLE staff (
    staff_id number,
    staff_details text
)

CREATE TABLE policies (
    policy_id number,
    customer_id number,
    policy_type_code text,
    start_date time,
    end_date time
)

CREATE TABLE claim_headers (
    claim_header_id number,
    claim_status_code text,
    claim_type_code text,
    policy_id number,
    date_of_claim time,
    date_of_settlement time,
    amount_claimed number,
    amount_piad number
)
SELECT policy_type_code FROM policies GROUP BY policy_type_code ORDER BY COUNT(*) DESC LIMIT 1
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: Find the type code of the most frequently used policy. ### Input: CREATE TABLE claims_processing (
    claim_processing_id number,
    claim_id number,
    claim_outcome_code text,
    claim_stage_id number,
    staff_id number
)

CREATE TABLE customers (
    customer_id number,
    customer_details text
)

CREATE TABLE claims_processing_stages (
    claim_stage_id number,
    next_claim_stage_id number,
    claim_status_name text,
    claim_status_description text
)

CREATE TABLE claims_documents (
    claim_id number,
    document_type_code text,
    created_by_staff_id number,
    created_date number
)

CREATE TABLE staff (
    staff_id number,
    staff_details text
)

CREATE TABLE policies (
    policy_id number,
    customer_id number,
    policy_type_code text,
    start_date time,
    end_date time
)

CREATE TABLE claim_headers (
    claim_header_id number,
    claim_status_code text,
    claim_type_code text,
    policy_id number,
    date_of_claim time,
    date_of_settlement time,
    amount_claimed number,
    amount_piad number
) ### Response: SELECT policy_type_code FROM policies GROUP BY policy_type_code ORDER BY COUNT(*) DESC LIMIT 1