16. The incremental B/C ratio between pavers C77 and A99. 17. In this assignment, the conclusion of the benefit/cost ratio as to the best paver coincides with the conclusion of the Net Present Worth (NPW) method. 18. B88's Internal Rate of Return (IRR). 19. C77's Internal Rate of Return (IRR). 20. The incremental Internal Rate of Return (AIRR) between pavers B88 and A99