Need help to answer this problem for my economy class. Thanks

Old Machine n Repair Value Salvage Value O&M CR(9%) OC(9%) AEC(9%) O $1,200 $5,000 1 $4,000 $2,000 $2,758 $2,000 $4.758 2 $3,000 $3,500 $2,089 $2,718 $4.807 3 $2,000 $5.000 $1,839 $3,414 $5.253 4 $1,000 $6.500 $1,695 $4.089 $5,784 5 $O $8,000 $1,594 $4,742 $6,336 New Machine n Investment Salvage Value O&M CR(9%) OC(9%) AEC(9%) $10,000 $6,000 1 $5,100 $2,000 $5,800 $2,000 $7,800 2 $4,335 $2,800 $3,611 $2,382 $5,993 3 $3,685 $3,600 $2.826 $2.754 $5,580 4 $3,132 $4,400 $2,402 $3,114 $5,516 5 $2,662 $5,200 $2,126 $3,463 $5,589The nomenclature of the equation to obtain the marginal AEC for the defender is: O Marginal AEC = 4,000(A/P, 9%, 1) + (3,500 - 3,000) O Marginal AEC = 3,000(P/A, 9%, 1) + (5,000 - 2,000) O Marginal AEC = 3,000(A/P, 9%, 2) + (5,000 - 2,000) O Marginal AEC = 2,000(A/P, 12%, 1) + (5,000 - 2,000)