Which Restriction on the Actions of Lobbyists Passed in 1996

Which restriction on the actions of lobbyists passed in 1996 is still in effect today?

A) relaxed control over the practice of honoraria
B) limited the size of individual gifts to no more than $50
C) banned travel of congressional representatives on corporate jets
D) allowed businesses to deduct lobbying costs as a business expense
E) prohibited businesses from deducting lobbying costs as a business expense