Correct option is A
In a velocity-time (v–t) graph, the slope of the graph represents acceleration. When the slope is positive, it indicates that velocity is increasing with time, meaning the object is accelerating. However, when the slope is negative, it indicates that velocity is decreasing with time. This decrease in velocity is known as retardation (or deceleration).
Mathematically, acceleration is defined as the rate of change of velocity with respect to time. Therefore, a negative slope means the rate of change of velocity is negative, which directly implies retardation. This is commonly observed when an object is slowing down, such as a car applying brakes.
