为了节省能量，某商场安装了智能化的电动扶梯。无人乘行时，扶梯运行得很慢；有人站上扶梯时，它会先慢慢加速，再匀速运转。一顾客乘扶梯上楼，恰好经历了这两个过程，如图所示。那么下列说法中正确的是 ( ) Options: A. 顾客始终受到三个力的作用 B. 顾客始终处于超重状态 C. 顾客对扶梯作用力的方向先指向左下方，再竖直向下 D. 顾客对扶梯作用力的方向先指向右下方，再竖直向下---**Question Stem:** 5. (09 安徽) 为了节省能量，某商场安装了智能化的电动扶梯。无人乘行时，扶梯运行得很慢；有人站上扶梯时，它会先慢慢加速，再匀速运转。一顾客乘扶梯上楼，恰好经历了这两个过程，如图所示。那么下列说法中正确的是 ( ) **Options:** A. 顾客始终受到三个力的作用 B. 顾客始终处于超重状态 C. 顾客对扶梯作用力的方向先指向左下方，再竖直向下 D. 顾客对扶梯作用力的方向先指向右下方，再竖直向下 **Chart/Diagram Description:** * **Type:** Schematic diagram illustrating a person on an escalator. * **Main Elements:** * **Person:** A simplified human figure (stick figure) is shown standing upright on one of the steps of the escalator. * **Escalator:** Depicted as an inclined structure with multiple steps, slanting upwards from the lower-left to the upper-right. * **Escalator Movement Direction:** A long, thin black arrow originates from below and to the left of the escalator and points upwards and to the right, parallel to the escalator's incline, indicating the direction of its motion. * **Force Arrows (from customer):** Two black arrows originate from the customer's feet and point towards the escalator step: * A prominent, thicker arrow points downwards and to the left, roughly parallel to the escalator's incline. This arrow represents a force exerted by the customer on the escalator. * A very thin, short arrow points vertically downwards from the customer's feet to the escalator step. * **Relative Position and Direction:** The customer is positioned on an escalator step, which is inclined upwards and to the right. The escalator moves in the upward and rightward direction. The prominent force arrow from the customer indicates a force exerted downwards and to the left on the escalator step.