EAC (Estimate and complete) is typically based on actual cost (AC) for work completed plus and ETC (Estimate to complete) the remaining work. Which of the following is a valid formula for calculating EAC?

A.
EAC= AC + [(BAC-EV)/(CUMULATIVE CPI* CUMULATIVE SPI)]

B.
EAC= BAC – AC

C.
EAC= 1-CPI

D.
EAC =EV + [1-(CUMULATIVE CPI* CUMULATIVE SPI)/BAC]

Explanation:
There are 4 types of EAC forecast calculation formulas available, but confused when to use each type.

EAC = BAC / CPI
EAC = ETC + AC
EAC = (BAC-EV) + AC
EAC = [BAC-EV / spi * cpi] + AC

EAC = AC + Bottom up ETC — Used when original estimate is fundamentally flawed
EAC = BAC / Cumulative CPI – Used if no variances have occured and same rate of spending will continue
EAC = AC + (BAC- EV) – Used when variances are atypical /irregular
EAC = AC + ( BAC-EV / Cumulative CPI * Cumulative SPI) – Used when variances are typical(regular). Assumes poor cost performance