The correct answer is option 2: 29-30%. This means that approximately 29-30% of the Earth`s surface is covered by continents.

To understand this, we need to know that the Earth`s surface is made up of land and water. The land portion consists of continents, which are large masses of land separated by oceans. The continents include Africa, Asia, Europe, North America, South America, Australia, and Antarctica.

When we talk about the percentage of expansion or coverage of continents, we are referring to the proportion of the Earth`s surface that is occupied by the continents. In this case, it is estimated to be around 29-30%.

It is important to note that this percentage may vary slightly depending on different sources and definitions of continents, but in general, option 2 provides the most accurate estimate.