4. Two alternatives are being considered to supply water from a reservoir to a local community. Option A is a tunnel and Option B is on open channel (steel flume with concrete-lined canal) Construction Economic Alternative Annual O&M cost Life (years) Salvage A-Tunnel $8,000,000$55,000 100 $0 B-Open Channel Steel Flume Canal Canal Lining $900,000 $1,000,000 $550,000 $0 $0 $25,000 $120,000 50 100 20 a. Draw the cash-flow diagrams b. Assuming an interest rate of 6%, determine the present worth of each alternative c. Which is the best alternative from an economic perspective