The correct answer is option 3, which states that carbon black is obtained by burning hydrocarbons in a limited supply of air.

To understand this better, let`s dissect each option:

Option 1 suggests that carbon black is obtained by heating wood at high temperature in the absence of air. However, this process would instead produce charcoal, which is different from carbon black.

Option 2 states that carbon black is obtained by heating coal at high temperature in the absence of air. While this process does produce a type of carbon called coke, carbon black is not typically produced through this method.

Option 3, the correct answer, explains that carbon black is obtained by burning hydrocarbons in a limited supply of air. Essentially, hydrocarbons are burned with a restricted amount of oxygen, which leads to the formation of carbon black. This method is commonly used in industrial processes to produce carbon black.

Option 4 suggests that carbon black is obtained by heating coal at high temperature in the presence of air. However, this process is more likely to form other carbon compounds, such as carbon dioxide, rather than carbon black.

In conclusion, carbon black is obtained by burning hydrocarbons in a limited supply of air, as mentioned in option 3.