Michael​ Kremer's research suggests that higher population might stimulate technological progress. How can higher population stimulate technological​ change?

a. A rise in population at first leads to a decline in per-capita output, and the growth rate of per-capita output will decrease permanently.
b. The research may be just conjecture on the role of technology based on the growth of the world population.
c. A higher population puts more pressure on limited available resources, thereby increasing incentives to spur technological change.
d. A higher population immediately increases α, which, in turn, increases the balanced growth path.