In order to discount multiple cash flows to the present, one would use:

Recall the formula for the present value of an ordinary annuity: The formula is \( PV = C \times \frac{1 - (1 + r)^{-n}}{r} \), where \( PV \) is the present value, \( C \) is the cash flow per period, \( r \) is the discount rate per period, and \( n \) is the number of periods.

Compare the other options provided: The future value of a single sum formula calculates the value of a single cash flow at a future date, the current ratio formula measures liquidity, and the straight-line depreciation method is used for allocating the cost of an asset over its useful life. None of these are relevant for discounting multiple cash flows.