Last year, Joan bought 50 pounds of hamburger when her household ’s income was $40,000. This year, her household income was only $30,000 and Joan bought 60 pounds of hamburger. All else constant, Joan's income elasticity of demand for hamburger is_________.
A.
negative, so Joan considers hamburger to be an inferior good
B.
positive, so Joan considers hamburger to be a normal good and a necessity
C.
positive, so Joan considers hamburger to be an inferior good
D.
negative, so Joan considers hamburger to be a normal good but not a necessity