The image shows a graph of a function P. Observing the graph, it is a parabola opening upwards with its vertex at (0,0). This is the characteristic shape of the quadratic function y = x². The vertex form of a parabola is y = a(x - h)² + k, where (h,k) is the vertex. Here, (h,k) is (0,0) and a=1.

Therefore, the equation is: $P=x^2$

Final Answer: The first option (top-left image) which is the graph of y = x².