Spring tides occur when the gravitational forces of the Sun and the Moon combine to have the maximum effect on the tides. The correct answer is option 2, which states that spring tides occur on both full moon days and new moon days. During these phases, the Sun, Moon, and Earth are aligned in a straight line, causing the gravitational pull from both the Sun and the Moon to be in the same direction. This alignment results in the highest high tides and the lowest low tides of the lunar cycle. It is important to note that spring tides have nothing to do with the season of spring, but rather refer to the "springing forth" or increasing of the tide levels.