In the figure on the right, B1 is the initial budget line and the consumer chooses X* as his optimal bundle and as the money income of the consumer rises, his budget line will shift outward and parallel to itself to B2. At the budget line B2 and the indifference curve I4, the consumer will choose X'. Subsequently, as the income rises further, the budget line will again shift outward and parallel to itself to B3, where, the consumer will choose the optimal bundle X".