An inference is a conclusion of sorts or an idea. So as you read those lines and read the answer choices given, which of the choices is a drawn conclusion or idea from what you just read.
For example, if you were to read the following lines: Johnny’s dog was barking and scratching the door. Johnny’s dog had not been outside for several hours.
What inference can you make from those two sentences? We can determine that Johhny’s dog needs to go outside to use the bathroom.