The correct answer is: B. convection.
Convection is the heat transfer mechanism that is most effective in removing heat from a hot object. When air is blown over a hot object, the hot air rises and is replaced by cooler air. This circulation of air helps to carry away heat from the object, resulting in a decrease in its temperature.
Conduction is the heat transfer mechanism that occurs when two objects of different temperatures are in contact with each other. Heat flows from the hotter object to the cooler object until the two objects reach the same temperature. Conduction is not as effective as convection in removing heat from a hot object.
Radiation is the heat transfer mechanism that occurs when electromagnetic waves are emitted from a hot object. These waves travel through the air and can be absorbed by other objects. Radiation is the least effective heat transfer mechanism for removing heat from a hot object.
In conclusion, the increase in heat dissipation by air blasts is due to increase in convection.