Answer:
Option a
Explanation:
The action of the rapid rubbing of the hands are a result of chemical reaction and responses that takes place inside our body.
When we rub our hands together, that shows the mechanical motion of the body or we can say that while rubbing hands chemical energy gets converted to mechanical energy (here, Kinetic energy).
While rubbing, due to friction, heat is produced and hence we can say that this mechanical energy has transformed to heat energy.
Thus the conversion here is from chemical to mechanical to heat energy.