What is a suitable flow model for a fluid?

A)
Molecular approach
B)
Finite control volume approach
C)
Infinitesimal fluid element approach
D)
All the three models can be used based on the need

Correct Answer :   All the three models can be used based on the need


Explanation : The finite control volume considers a finite volume which may be either fixed in space or moving along a fluid. The infinitesimal small element considers a finite element which may be either fixed or moving along with the flow. The molecular approach is a microscopic approach and can be applied to atoms and molecules.