>This can work, but it increases complexity of C, and the logic gets messy as well, as the code gets riddled with if blocks like "if called from A then do this

>This can work, but it increases complexity of C, and the logic gets messy as well, as the code gets riddled with if blocks like "if called from A then do this block of logic". Instead of doing this, the author should consider decomposing C even more. The former is logical cohesion, the latter is functional cohesion.