Power question from JEE Main 2020 (3 Sep, Shift 2)

Answer: (b)

1. Constant power gives $v \propto t^{1/2}$, so $s \propto t^{3/2}$.
2. $s \propto t^{3/2}$ starts at the origin, and its slope $\dfrac{ds}{dt} \propto t^{1/2}$ keeps increasing.
3. So the graph curves upward (concave up) from the origin.
4. So the answer is (b).