Hello, sorry this answer is late, I just wanted to give some clarification as to why the answer is Gambia.
So the country with the lowest standard of living is Gambia. This is because the statistics in each category is significantly lower than the rest. If you look at a DTM map/Demographic Transition Model, you can see how a country grows from a developing country to a developed country.
Gambia can be considered a stage 2 developing country. Since the statistics are low, we can infer that the country cannot live comfortably yet they have to face survival due to circumstances they face such as unsanitary water. Unclean water is a big reason for why a country may not be developing as well as other countries. Resources may be scarce as well as having a low/weak economy.
However since it is a stage 2 developing country we can see on the chart that the statistics are climbing up to the rest of the countries. Since progress is being made, we can tell that this is a stage 2 developing country. *Note that no country is a stage 1 country unless it is a small tribe. Stage 1 countries are very rare*
I hope this helps anyone in the future :)
