Which of the following is false, regarding the Solow model of economic growth?

a. Capital accumulation can only produce transient (i.e. temporary) growth.

b. With a finite population, an unlimited amount capital can accumulate.

c. In the two-country model of technological change, increasing the R&D spending rate in the leading country permanently increases growth, but increasing the R&D spending rate in the following country only transiently increases growth.

d. Positive feedbacks between the investment rate and per-capita income can lead to alternative high-and low-affluence stable states.