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

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