12. 安裝在鍋爐的最低處,採用無底座閥(Seatless Valve)不易積水垢及其他沉積物的閥,稱為下列何者?(A)給水停止閥 (FeedWater Stop Valve)(B)吹洩閥 (Blow-off Valve)(C)止回閥 (Check Valve)(D)蒸汽停止閥 (Steam Stop Valve)