Final answer:
The correct answer is 4) Not mentioned, as the provided statement only discusses the neighbor walking her dog, with no reference to who walks a pet goat.
Step-by-step explanation:
The question 'Who walks the neighbor's pet goat every other day?' presents four options: 1) Marceline the Vampire Queen, 2) The neighbor, 3) The pet goat, 4) Not mentioned. Based on the reference statement given, 'I see my neighbor walking her dog every morning. So my neighbor will probably walk her dog this morning.', there is no information about who walks the pet goat. The only mentioned activity is the neighbor walking her dog. Therefore, the correct answer to the question is 4) Not mentioned, because the information provided does not include anyone walking a pet goat.