Final answer:
The Earth took approximately 4.5 billion years to reach its present form after being detached from the sun. This was primarily due to the process of gradual accretion and cooling. Further processes like volcanic activity, atmospheric development, and the evolution of life also contributed to Earth's present form.
Step-by-step explanation:
The Earth primarily took approximately 4.5 billion years to reach its present form after being detached from the sun, according to most scientists. This timeline corresponds with option B in your query. After the sun formed, there was a protoplanetary disk of gas and dust remaining. Over time, due to gradual accretion, Earth-like planets formed. Accretion is a process whereby dust and gas molecules come together to form larger bodies—this process, combined with the cooling of the Earth's crust, took around 4.5 billion years.
Accretion and Cooling of the Earth
The process of accretion was followed by a cooling phase. As these newly formed planets, including Earth, cleared their orbits around the sun, the heat generated by the gravitational binding reduced, and the surfaces of the planets began to cool and solidify. This process marks the beginning of Earth's geological history, and it took millions of years. There were also many other following processes like volcanic activity, atmospheric development and finally the beginning of life which steered Earth towards its current form.
Learn more about Earth Formation