1) An economy produces only agricultural products (x) and manufactured goods(y). A quarter of the land in the country is arid and not suitable for agricultural products. Therefore, if half of the arid land is not used at all: a) The economy could be productively efficient when the opportunity cost of x (agricultural products) is infinite. b) The economy could be productively efficient when the opportunity cost of y (manufactured goods) is zero. c) The economy could be productively inefficient with infinite opportunity cost for the production of x (agricultural products). d) The economy could be productively inefficient with infinite opportunity cost for the production of y (manufactured goods). 2) If good x is a normal good and y is it's gross substitute then: a) Income elasticity of the demand for x is less than zero and so is the cross price elasticity. b) Income elasticity of the demand for x must be greater than zero and cross price elasticity must be less than zero. c) Income elasticity of the demand for x must be less than zero and cross price elasticity greater than zero. d) Income elasticity of the demand for x must be greater than zero and so must be the cross price elasticity