(A)5號(hào) (B)7號(hào) (C)8號(hào)
(A)5號(hào)閥 (B)7號(hào)閥 (C)9號(hào)閥
(A)2項(xiàng) (B)3項(xiàng) (C)4項(xiàng) (D)5項(xiàng)