f sunk costs should not be relevant when making a decision, why do people consider them? In your answer, describe the sunk cost effect/fallacy (Keil et al., 2000; Wang and Keil, 2000; Hammond et al., 1998; Keil et al. 1995; Klimek 1997; Colon and Leatherwood, 1989; Northcraft and Neale, 1986; Conlon and Garland, 1993; Garland and Conlon, 1998). Further, in your answer, describe the following theories as potential explanations for the sunk cost effect/fallacy: a. Prospect theory b. Completion effect c. Self-justification theory d. References for these theories include: Keil et al., 2000; Wang and Keil, 2000; Keil et al., 2000; Klimek, 1997; Colon and Leatherwood, 1989; Brockner, 1992; Whyte 1986