On Some Days Gustav Makes His Own Salad for Lunch

Multiple Choice

On some days Gustav makes his own salad for lunch, preferring to use either iceberg or romaine lettuce, topped off with lots of fresh tomatoes. For Gustav, the cross-price elasticity of demand for iceberg lettuce with respect to romaine lettuce is _____, and the cross-price elasticity of demand for iceberg lettuce with respect to tomatoes is _____.

A) positive; negative
B) negative; positive
C) zero; positive
D) negative; zero