What has not been a problem facing el salvador in the early twenty-first century

the answer is: natural disaster

El-Savador is located in an area called the 'ring of fire'. This ring of fire exist on top of volcanoes, so the danger of earthquake and eruption always exist.

During the early twenty-first century, there was very little volcanic activity on the ring of fire, which is why el savador hasn't been facing any huge problem regarding natural disaster in early twenty-first century

d) in the state of iowa