Answer:
the equation in letter D is a linear function.
The drawing shows a circle, with the two lines forming a cross assumed to be perpendicular to each other, so this is most likely to be a square, as the four points at which the perpendicular lines intersect with the circle can be connected to form a square.
We would need 3 points for an equilateral triangle, 5 for a pentagon, and 6 for a hexagon, which do not fit the current steps.
Call x the distance from home plate to second base.
There is a right triangle formed by homeplate, first base and second base. The sides of this triangle are 80 feet and 80 feet. The hypothenuse meets Pythagoras theorem:
x^2 = 80^2 + 80^2 = 2(80)^2
x = 80√2
Then the answer is the option D.
The first bullet is the answer