The twin hills found in the north and central part of the quadrangle bellow show the stars and in order to cross the golden gate mountain which is a national highland park.
The highest path to reach the gate will be through the flattest topographic that is seen in the curve along with the option d as a sloping tableland.
Well if you mean what does the controlled part of a scientific investigation, it is the part of the investigation that will be your control or your base, untouched, original, data and such.