To improve its standard of living, a nation’s economy must

Aremain stable.
Bgrow through innovation.
Creach economic equity.
Dallow the central government to make economic decisions.

Verified Answer :

To improve its standard of living, a nation’s economy must
 grow through innovation.
because it a method of bringing new ideas methods in use so its the best way
so option B is correct
 hope it helps

I believe the answer is: grow through innovation. 

The more innovation that a country make, the more products would be available that can make people's task much more easier in all sectors. This would make people have access to various technology that would help their general wellness such as modern medicines for health, modern tools for productivity, etc.