The correct option is D Crouching in an open field
During lightning, tall trees are prone to get struck during lightning, same thing goes to ponds and lakes which are large. Running up a hilly region during lightning will decrease a person's distance from clouds, which will increase the chances of lightning strike.
Comparatively it is better to be away from water bodies and tall trees, so one can be in a crouching position in the open field to make the least chance of the lightning strike.