Toni's Tools Is Comparing Machines to Determine Which One to Purchase

Toni's Tools is comparing machines to determine which one to purchase. The machines sell for differing prices, have differing operating costs, differing machine lives, and will be replaced when
Worn out. These machines should be compared using:

A) Net present value only.
B) Both net present value and the internal rate of return.
C) Their effective annual costs.
D) The depreciation tax shield approach.
E) The replacement parts approach.