Need Help for select

Hi all,

i need help to build a select query or plpgsql-fucntion
for the following tables.

create table a (
id int,
name varchar(20)
)

create table b (
a_id int,
c_id int
)

create table c (
b_id int,
d_id int
)

create table d (
id int,
name varchar(20)
)
Is it possible to build a select query that selects d.name for each a.name where
a.id = b.a_id and d.id = c.d_id and each b.c_id must exist in c.b_id.

Example:
a: b: c : d:
id | name a_id | c_id b_id | d_id id | name
----|------- -------|----- -------|----- -----|--------
1 | A_Name1 1 | 1 1 | 1 1 | D_Name1
2 | A_Name2 1 | 2 2 | 1 2 | D_Name2
3 | A_Name3 2 | 1 3 | 2 3 | D_Name3
4 | A_Name4 3 | 3 4 | 2
3 | 4 5 | 3
4 | 5

i wish to have to following result:
--------|--------
A_Name1 | D_Name1
A_Name3 | D_Name2
A_Name4 | D_Name3

I hope someone could understand the problem

Thanks in advance and sorry for my bad english