I would say option C)
B) should not even be in question. I think. Cyclical companies have varying sales numbers throughout seasons.
A) should also never be used, a growing company will have very different numbers on the consequent year.
D) The problem here is that you can get analyst estimates for revenues, earnings, but you won’t be able to fill in other details like CapEx, acquisitions, depreciations, working capital.
C) is a good way to do it. And keep updating this as more and more quarterly reports come out. - called Trailing 12 month numbers
Here, the only level of consistency that you should be aiming for is to use the most updated versions of the numbers you can. Even if you say, have accounting numbers are weeks or even a month old, you will still use todays risk free rates, betas, etc.
CapEx is usually found in the statement of cash flows, maybe indirectly in the balance sheet.
What should constitute CapEx?
A CapEx is any expenditure that creates benefits over many years as opposed to operating expense like labour material where it creates revenue this year.
Now look at the pic above and answer: