In each of the following pairs of goods, identify the one which you would expect to have

Question:

In each of the following pairs of goods, identify the one which you would expect to have a greater price elasticity of demand. Briefly explain your answers.
a) Butter versus eggs
b) Trips by your congressman to Washington (say, to vote in the House) versus vacation trips by you to Hawaii
c) Orange juice in general versus the Tropicana brand of orange juice