Solow model demonstrates the pre-eminence of productivity gains in determining both capital accumulation and economic growth. An obvious extension of that model is that, barring impediments to trade or other types of market failures, all countries with access to the same technology should grow at the same rate over the long run (in per capita terms)
The three goals of policymakers then should be...
a) Promoting trade barriers
b) Encouraging market failures
c) Enhancing productivity gains
d) Limiting access to technology