In each of the three circumstances (a, b, and c below), determine which of the following conclusions (1, 2, or 3) holds and justify your answer:
(1) John and Mary have identical tastes.
(2) John and Mary have different tastes.
(3) We can't tell whether John and Mary have identical tastes.
a. John and Mary have the same budget line and choose different baskets.
b. John and Mary have the same budget line and choose the same basket.
c. John and Mary have crossing budget lines and choose the same basket.