Because of nigeria’s instability, major oil companies like exxon-mobile have not invested in the country.

The statement is true.

Nigeria is anything but stable country and there are multiple factors that make too big of a risk for foreign big investments in the country, including the oil and gas industry. Some of the problems that push back investments are:

- Oil spills
- Pipeline vandalism 
- Crude oil theft
- Kidnapping
- Pollution
- Old deteriorated infrastructure 
- Terrorist organizations

It is true that Exxon-Mobile is devesting in Nigeria because of it's instability.

Explanation:

After 25 years, Exxon-Mobile corporation has been contemplating to exit its sale of the stake in Nigeria. It is planning to ramp off the divestitures by 2025. Due to the military violence and oil spills from the damages of the pipelines, many international companies including Exxon are seeking to lower their holdings. According to the Chairman of the Exxon Mobile Corporation, pollution in Niger delta, insufficient pipeline infrastructure, crude theft, fuel pricing, performance optimization are the areas to be re-looked for further investments.

As someone who have lived in northern moravia at industrial steel and coal city of ostrava, the closest point is b), but it is questionable. i am not sure how to compare efficiency of largest steel mill in czech republic in comparison to china which is the biggest exporter, but czech steel factories were modernized and run more efficient that 25-35 years ago, and been privatized and owned by mittal. the workforce had been shrinking, so not exactly sure what that c is pointing to (aging of workforce, size of it, or quality). northern moravia is a part of larger coal basin that extend to poland with large coal deposits. this was foundation for the steel industry in the 1800's together with large ore deposits that was mined in proximity of the beskidy mountains less than 25 miles from ostrava. the iron ore mines had been depleted for several decades, and since the late 70's when communists run the country, they were already importing soviet iron ore. coal mining within city of ostrava cased to exist in the 1990's due environmental issues, and also cost. the mines were getting deeper and more costly to operate and there is no more mining within ostrava. couple mines are still in operation in karvina county which is next to ostrava. currently the coal deposits south of the city were not opened due environmental issue which would mean destruction of third largest mountain range in the country. therefore, my conclusion is is b, as the ore and coal resources been shrinking. the biggest challenge not mentioned here is of course competition from russia, ukraine, and china, which can produce steel much cheaper.