The application of 'computational fluid dynamics' $($CFD$)$ in civil engineering is primarily for:

A$.$ Analyzing the effects of liquid and gas flow through and around structures to predict potential impacts under various conditions.

B$.$ Simulating pedestrian movement patterns in public spaces.

C$.$ Calculating the optimal pathways for electrical and plumbing systems within buildings.

D$.$ Designing aesthetically pleasing water features in large$-$scale developments.