Final answer:
The condition often associated with macrophages accounting for more than 15% of the total nucleated cell count is bacterial infections.
Step-by-step explanation:
The condition often associated with macrophages accounting for more than 15% of the total nucleated cell count is A) Bacterial infections. Macrophages are immune cells that play a key role in phagocytosis, the process of engulfing and destroying pathogens. In bacterial infections, macrophages are activated to clear the invading bacteria by engulfing and destroying them.