Hi @meisen, thanks for your post. There is no information given in the passage about what materials "other than metal" Noguchi used in his sculptures after ending his association with Brancusi. The passage introduces Noguchi's work for Brancusi (paragraph 2) and then says that "in 1929, *after* returning to the United States," Noguchi met Fuller (lines 29-30). We then learn about Noguchi's sculpture of Fuller, in which he used nickel steel - a kind of metal. But we don't know what materials *other than* metal Noguchi used. Thus, (C) is wrong.
There is textual evidence to answer the question posed in answer choice (D), however - we know there was in fact a "favorable critical response to his creation of a positive-light sculpture." See paragraph 5 (lines 56-60 - "At the moment when his exploration had won critical recognition of the genius of his original and fundamental conception . . ..").
