如图所示为小明和小华在课外活动时的s−t 图像，关于这段运动，以下描述错误的是( ) A. 小华的平均速度等于小明的平均速度 B. 小华的速度始终大于小明的速度 C. 小明做匀速直线运动 D. 小华做减速运动 ---Chart Description: The image displays a 2D diagram within a coordinate system with x and y axes. Point A is located near the origin. A dotted curved line represents a path from point A to point B. A dashed straight line represents a path from point B to point C. There is a dashed horizontal line segment above point A and a dashed vertical line segment to the right of point C, suggesting boundaries or reference lines. A label "从A到B" (From A to B) is placed near the curved path. A label "从B到C" (From B to C) is placed near the straight path. An arrow labeled "力 F" (Force F) is shown near the path from A to B, pointing roughly inwards towards the concavity of the curve. An arrow labeled "速度 v" (Velocity v) is shown along the path from B to C, indicating motion in the direction of the straight line path. Textual Information: Labels: A B C x y 力 F (Force F) 速度 v (Velocity v) 从A到B (From A to B) 从B到C (From B to C)