Answer:
b) adding to its capital stock
Explanation:
It is correct to say that a country accelerates its economic growth by increasing its capital stock, as the index that measures economic growth in a country is the GDP, which is the country's gross domestic product, that is, everything that the country produced during the period of one year.
So when there is an increase in the capital stock in the economy, whether by an increase in investment in the country or by industrial activity, it means that there is an increase in the production of goods, an increase in employment, an increase in purchasing power and therefore an increase in the index that measures economic growth, GDP.