How do I copy an element of composite type array into csv file?

[a]

Hi suppose I have composite type and table


create type A as(
    x float8,
    y float8
);


create table B(
    Ay A[]
);


insert into B
values(array[
    (1,2)::A,
    (3,4)::B]
);


Now I would like to export the first element of table B into an csv file:


COPY B(Ay[1])
to 'E:/products_199.csv'  DELIMITER ',' CSV HEADER;



The code above reported an syntax error.


How should I do it??


Thank you so much!


Shore