Answer: Option (b) is the correct answer.
Explanation:
When a fluid is heated then cooler material (more dense) sinks at the bottom whereas warm material (less dense) rises at the top. This process of exchange of materials is known as convection process.
For example, boiling of water in a pot represents convection process.
Whereas when two objects of different temperature are kept adjacent to each other then transfer of heat occurs from hotter to colder object.
For example, a metal spoon placed in a boiling water represents conduction process.
Thus, we can conclude that convection and conduction is the type of heat transfer that contribute to the increase in temperature of the spoon.
