John sold his used bike for $75, even though he paid over $400 for it three years ago. Assuming John follows the principles taught so far, what can we infer from John's behavior? a. John's PISP must...

John sold his used bike for $75, even though he paid over $400 for it three years ago. Assuming John follows the principles taught so far, what can we infer from John's behavior?

a. John's PISP must lie between $75 and $400.

b. John did not violate the "sunk cost" principle.

c. Around a cycle of ownership, the buying price of an item need not equal its selling price.

d. John's PIBP for the bike must have been below $400 three years ago when he bought it.