在三角形ABC中，若∠ACB=90°，CD⊥AB，垂足为D，则下列线段的长度可以表示为点B到直线AC距离的是（$\qquad$） A. BD B. BC C. AB D. CD---**Chart/Diagram Description:** * **Type:** Geometric figure, specifically a right-angled triangle with an altitude drawn to the hypotenuse. * **Main Elements:** * **Points:** Points A, B, C, and D are labeled. * **Lines:** Line segments AC, BC, AB, and CD are shown. AB is a straight line. * **Shapes:** A large triangle ABC is formed. Triangle ACD and triangle BCD are also formed. * **Angles:** There is a right angle symbol at vertex C, indicating that ∠ACB is a right angle (90°). There is a right angle symbol at point D on line segment AB, indicating that line segment CD is perpendicular to line segment AB, thus ∠CDA is a right angle (90°) and ∠CDB is a right angle (90°). * **Labels and Annotations:** The vertices and the foot of the perpendicular are labeled with letters A, B, C, and D. Right angle symbols are present at C and D. * **Relative Position and Direction:** C is the vertex where the right angle of the large triangle ABC is located. A and B are the other two vertices, forming the hypotenuse AB. D is a point on the line segment AB. CD is a line segment connecting C to D, and it is perpendicular to AB at D. A is to the left of D, and D is to the left of B on the line segment AB. C is above the line segment AB. AC is the side connecting A and C. BC is the side connecting B and C. AB is the side connecting A and B. CD is the line segment from C to D.