The correct answer is A) The Neptunians are very concerned about our rapid progress as a species.
We Neptunians have been watching Earth’s progress for a long time. It has warmed our hearts to watch you move forward. The statement that best identifies the inferential meaning in this passage is "The Neptunians are very concerned about our rapid progress as a species."
The inferential meaning or inference from a sentence is what we can interpret from that statement, according to the context expressed. In this case, when the Neptunians say "It has warmed our hearts to watch you move forward," they are trying to say that they are very pleased with the humanity advances on planet Earth.