28. 如圖(一)所示的桁架屬於哪一類型? (A)芬克式桁架 (Fink Truss) (B)鋸齒狀桁架 (Saw-tooth Truss) (C)曲弦式桁架 (Bowstring Truss) (D)華倫式桁架 (Warren Truss)