Gas stations can price the products that they sell in their convenience store a little bit higher because?
a these products are usually substitutes to the gas sales and the demand for gas is inelastic
b these products are usually substitutes to the gas sales and the demand for gas is elastic
c these products are usually complements to the gas sales and the demand for gas is elastic
d these products are usually complements to the gas sales and the demand for gas is inelastic