How often do spring and neap occur?

Occurrence of spring and neap:Spring tides occurs twice in every month annually. When the 'new or full moon' occurs than the 'gravitational pull of sun' is added or supplemented to the gravitational pull of earth's moon, it causes a surge in the ocean tides.In other words the high tide became even more higher and low tides much lower. This are called spring tides.After the seven days of spring days, the moon and sun appears at a right angle towards each other. The surge in the ocean tides becomes normal and the tides became moderate. These are called neap tides.

Ibelieve the answer is c. map projections.hope my answer has you : )

Answerhighlands and forests;