$**$Chemical Engineering: Reactor Types$**$

$**$Question:$**$

In chemical engineering, which type of reactor design involves the continuous addition of reactants and removal of products while maintaining a constant composition within the reactor?

A$)$ Batch reactor

B$)$ Plug flow reactor

C$)$ Continuous stirred$-$tank reactor $($CSTR$)$

D$)$ Packed bed reactor