Unemployment is high in iran among young men due to their lack of skills. what could be one cause for this problem? 1. lack of investment in human capital 2. lack of investment in machinery 3. high investment in the military 4. lack of natural resources

I would say 1) lack of investment in human capital.

They definitely need investments focused on human development and education. Without this, there will be continued lack of skill and unemployment. Human capital is the skills and knowledge a person possesses as it relates to their value to the country (or business if working in smaller terms).

Hope this helps!! :)

d is the answer for sure