(Solved): 6. The diagram shows an indifference map and two budget lines. When the consumer's budget line shif ...

6. The diagram shows an indifference map and two budget lines. When the consumer's budget line shifts from \( B L 1 \) to \( B L 2 \), consumption changes from point \( W \) to point \( Z \). What do these changes indicate about the nature of goods \( X \) and \( Y \) ? ( )