The most relevant incentive for a national government to improve education and literacy in their country is:
B. Educated populations have a higher standard of living than uneducated populations.
Improving education and literacy can lead to a more skilled workforce, increased economic productivity, and overall better quality of life for citizens, which in turn can boost the economy and contribute to social stability. While there may be elements of truth in the other options, option B emphasizes the broader socio-economic benefits associated with a well-educated populace.