Option C is the correct answer.

Watt is a derived unit. Watt is the unit of a derived physical quantity, Power. Power is defined as the rate of doing work, $\rm P = \frac{W}{t}$. Because of its dependence on other physical quantities for existence, it is a derived quantity. Similarly, watt ($\rm W = kgm^{2}s^{-3}$) is a derived unit due to its dependence on kilogram, meter, and second.