a) Partial derivative
b) Instantaneous derivative
c) Total derivative
d) Local derivative

Answer: c
Explanation: Substantial derivative is the same as total derivative. However, total derivative is completely mathematical.
\(\frac{DT}{Dt}=\frac{\partial T}{\partial t}+u \frac{\partial T}{\partial x}+v \frac{\partial T}{\partial y}+w \frac{\partial T}{\partial z}\)
\(\frac{DT}{Dt}=\frac{\partial T}{\partial t}+u \frac{\partial T}{\partial x}+v \frac{\partial T}{\partial y}+w \frac{\partial T}{\partial z}\).