In the early 20th century, Constantin Brancusi's sculpture Bird in Space sparked considerable debate about the definition of art. Tax authorities argued in court that the abstract sculpture, which featured a long, sleek form without any identifiable features, should not be classified as art. Brancusi ultimately won the case, but the legal battle highlighted the ______ dividing line between "art" and "manufactured object".

Which choice completes the text with the most logical and precise word or phrase?
Choose 1 answer:
Choose 1 answer:
(Choice A) rigid
A
rigid
(Choice B) unanimous
B
unanimous
(Choice C) tenuous
C
tenuous
(Choice D) straightforward
D
straightforward