The growth rate of per capita GDP in the Romer model depends on the number of workers engaged in research. However, the country of Luxemburg, which has far fewer researchers than the U.S.grows at a rate faster than the U.S. and has a higher per capita GDP. How can the Romer model explain this difference in growth rates? Select one: 0.2. Due to the nonrivalry of ideas, the economy of Luxemburg grows because the model is based on ideas created throughout the world, not just within that country. O b. Luxemburg is richer so according to the principle of transition dynamics, its economy should grow faster. Oc. The productivity of researchers or the share of workers engaged in research must be smaller in Luxemburg than in the US. Od. This difference in growth rates is not consistent with the Romer model The model fails to predict the facts. O