Last Year, Housam Purchased 60 Kilos of Potatoes to Feed

Last year, Housam purchased 60 kilos of potatoes to feed his family of five when his household income was US$30,000. This year, his household income fell to US$20,000 and Housam purchased 80 kilos of potatoes. With all else constant, Housam's income elasticity of demand for potatoes is

A) positive, so Housam considers potatoes to be a normal good and a necessity.
B) negative, so Housam considers potatoes to be an inferior good.
C) positive, so Housam considers potatoes to be an inferior good.
D) negative, so Housam considers potatoes to be a normal good.