The correct answer is option 4: Venus.

Venus is known as the "morning star" and the "evening star" because it is the first planet to appear in the evening sky and the last to disappear in the morning sky. This is due to the fact that Venus is the closest planet to Earth and also orbits the Sun faster than any other planet.

During its orbit, Venus reaches its maximum angular separation from the Sun when viewed from Earth, which is why it can be seen in the morning or evening. When Venus is visible in the morning, it is called the "morning star," and when it is visible in the evening, it is referred to as the "evening star."

It is important to note that while the term "morning star" and "evening star" are used to describe Venus, they are not specific to Venus alone. In fact, other planets like Mercury, Mars, and Jupiter can also be called the "morning star" or the "evening star" depending on their visibility in the morning or evening skies.