Answer:
An increase in the available water in an ecosystem.
Step-by-step explanation:
An abiotic factor of an ecosystem is a non-living factor.
"A decrease in the number of available producers in the area. " Would be a biotic factor and would affect the environment for the worse. It would be the same with the second option too.
The third one is an abiotic factor but it would affect the environment for the worse.
The best answer would be the first option.
Hope this helps.