I would choose "C" on this.
Consider the first sentence of the stem :
" Economies in which a high percentage of resources are invested in research and development show greater growth in the long run
than do those in which resources are channeled into consumption "
the conclusion says:
"To grow as fast as
Japan has in the past three decades, the USA needs to change tax code..."
Here, the main point is to grow as fast as and not in long run so only "C" says USA need not to change anything because "countries with high consumption rates prosper in the short run anyway.
It would be interesting to know OA
Perseverance, Hard Work and self confidence