DECLARE	@TableA TABLE
	(
		A_ID INT
	)

INSERT	@TableA
SELECT	1 UNION ALL
SELECT	2 UNION ALL
SELECT	4

DECLARE	@TableB TABLE
	(
		A_ID INT,
		B_ID INT,
		C_ID INT
	)

INSERT	@TableB
SELECT	1, 2, 3 UNION ALL
SELECT	2, 4, 6

DECLARE	@TableC TABLE
	(
		C_ID INT,
		C_TYPE INT
	)

INSERT	@TableC
SELECT	3, 3 UNION ALL
SELECT	6, 4

SELECT	*
FROM	@TableA

SELECT	*
FROM	@TableB

SELECT	*
FROM	@TableC

-- visakh16
Select a.A_ID
from @TableA a
left join @TableB b on a.A_ID = b.A_ID
left join @TableC c on b.C_ID = c.C_ID And c.C_TYPE = 4
WHERE b.A_ID IS NULL

-- Peso
SELECT		a.A_ID
FROM		@TableA AS a
LEFT JOIN	(
			SELECT		b.A_ID
			FROM		@TableB AS b
			INNER JOIN	@TableC AS c ON c.C_ID = b.C_ID
			WHERE		c.C_TYPE = 4
		) AS z ON z.A_ID = a.A_ID
WHERE		z.A_ID IS NULL