When are tides highest? a. during the moon’s first quarter phase b. when the sun, earth, and the moon are nearly in a line c. during the moon’s third quarter phase d. when the moon is at a right angle to the sun

The correct answer is option b, that is, when the Sun, Earth, and the moon are nearly in a line.

Explanation:

The low and high tides are caused by the moon. The gravitational force of the moon produces something known as the tidal force. This force makes the Earth and its water to bulge out on the side nearest to the moon and the side far away from the moon. These bulges of water are considered as high tides.  

Similarly to the moon, the Sun also causes tides, but, they are smaller in comparison. However, when the Earth, moon, and the Sun line up, that is, which takes place during the new moon or the full moon, the solar and lunar tides reinforce each other, resulting in more extreme tides, known as spring tides. The spring tides are considered as the highest tides.