If a Challenger Is Different from the Defender, and the Challenger

Multiple Choice

If a challenger is different from the defender, and the challenger does not repeat, replacement decision should be based on

A) economic life of the first challenger only.
B) comparison of the defender with the last challenger.
C) marginal costs of the sequence of all challengers.
D) all possible combinations of the defender and all challengers over some study period.
E) installation costs of all challengers.