Contour lines are the lines of equal elevation. There are several contour lines shown in the map by representing A, F, E, C, D, and B.
In the map, the point C is in the eastern direction forming a steeper slope from the central A point. And the similar location that is at the same elevation like point C is the point D but that is towards the western side (opposite side) of the topography. The location D forms a much gentler slope from the central A position extending towards the western side.
Therefore, the location C and D are in the same elevation.
Hence the correct answer is option (C).
the offspring would all be white. if the parents are both white flowers then they have the genotype rr, which when crossed results in an all white punnet square.