All fossil fuel power types share this disadvantage:

a
they add carbon dioxide to the atmosphere, causing global warming
b
they add sulfur compounds to the atmosphere, causing acid rain
c
they do not work when the sun is not shining
d
they are more expensive than other energy sources

They add sulfur oxide to the atmosphere causing acidic rain.

Explanation:

At combustion , they release pollutants like sulfur and Nitrogen oxides to the atmosphere which contributes to the formation of acidic rain and smog among other negative consequences.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.