Deceleration appears as a decreasing slope on a distance-time graph

Steps:

• Identify the slope of each region, as slope represents speed (gradient = velocity).
• Constant slope means constant speed (no acceleration).
• Increasing slope means increasing speed (acceleration).
• Decreasing slope means decreasing speed (deceleration).

Why C is correct:

• Region C has a progressively shallower slope, indicating decreasing velocity per the definition of gradient as instantaneous speed.

Why the others are wrong:

• A: Constant steep slope shows uniform motion at constant speed.
• B: Steepening slope indicates positive acceleration.
• D: Flat or zero slope means the car is stationary.

Final answer: C