Susan spends her entire income on goods X and Y, which are the only two goods available for consumption. What would cause her budget line to shift from BLI (solid line) to BL2 (dotted line) in the diagram below? BL1 ................3..........5...................50 BL2 -X a) Income and the price of X (Px) both decrease while the price of Y (PY) stays unchanged. b) Income and PY both decrease while Px stays unchanged. c) Px and Py both increase while income stays unchanged. d) Px decreases while PY and income stay unchanged. e) PY decreases while Px and income stay unchanged