When Harry Potter was walking around the Hogwarts halls in the first book and find Snape fighting with the defence against the dark arts teacher. Snape turns around after hearing a noise made by Harry while he is under the cloak of invisibility but Harry moves away and finds the Mirror of Erised. In conclusion, Snape did almost find Harry but he got away.
I think the best answer would be A. since the number of prairie dogs decreased from the picture on the left to the picture on the right. Hope this helped :p
