A point is chosen at random within the square in the coordinate plane whose vertices are (0,0),(2020,0),(2020,2020), and (0,2020). The probability that the point lies within d units of a lattice point is \dfrac{1}{2}. (A point (x, y) is a lattice point if x and y are both integers.) What is d to the nearest tenth?
Answer Choices
A. 0.3
B. 0.4
C. 0.5
D. 0.6
E. 0.7