Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: You would think it would be a little intimidating. But for this tiny chihuahua, having a best friend 120 times his size is proving a great source of comfort. The diminutive Digby was abandoned on the street next to a set of bins. At just over a month old and weighing less than 1lb, he was freezing cold and perilously close to death. Fortunately, he was rescued by the RSPCA and taken to their Southridge centre in Hertfordshire - where he quickly became inseparable from 9st mastiff Nero. Scroll down for video New pals: Tiny chihuahua Digby with best friend Nero, a 9st mastiff who is 120 times the size. Digby was rescued by the RSPCA and taken to a centre in Hertfordshire where the two have quickly become inseparableTiny chihuahua Digby was abandoned on the street next to a set of binsHe was taken to RSPCA rescue centre where he met new best friend NeroThe 9st mastiff is 120 times the size and eats his pal's weight in pet foodDigby, who was perilously close to death, has taken on a new lease of life 
 Question:But staff at the RSPCA say he has been revived and come out of his shell after finding _.

Nero