Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth.
There are two main tides that are higher or lower than average. They occur twice monthly and are called neap and spring tides.
Neap Tides or Low Tides: When there is a low tide, the Moon faces the Earth at a right angle to the Sun so the gravitational force of the Moon and Sun work against each other. These tides are referred to as neap tides; a low tide or one that is lower than average.
Spring Tides or High Tides: When there is a high tide, the Sun, Moon and Earth are in alignment and the gravitational force is strong. These tides are known as spring tides and occur twice a month.
Hence, A is the correct option.