Interest groups spend hundreds of millions of dollars on lobbying efforts each year. However, why is it difficult to measure the effects of lobbying on policy outcomes? Selected answer will be automatically saved. For keyboard navigation, press up/down arrow keys to select an answer. a There are no public records available to track the activity of lobbyists. b Most of the effects of lobbying are unobserved. c Most lobbyists operate in secret. d Lobbying isn't all that effective