In this task, you're given a sentence and question. Based on the information provided in a given sentence, you should identify the shortest continuous text span from the sentence that serves as an answer to the given question. Answer the question using coreference resolution. Coreference resolution is the task of clustering mentions in text that refer to the same underlying real world entities. For example let's take a sentence 'I voted for Obama because he was most aligned with my values, she said.' Here in this example 'I', 'my', and 'she' belong to the same cluster and 'Obama' and 'he' belong to the same cluster. Now let's discuss another example , original sentence: 'I voted for Trump because he was most aligned with my values',John said. Now here is the same sentence with resolved coreferences: 'John voted for Trump because Trump was most aligned with John's values',John said. 

Sentence: John promised Bill to leave, so an hour later he left. Question: Who left?
John

Sentence: Lily spoke to Donna, breaking her concentration. Question: Whose concentration?
Donna's

Sentence: There are too many deer in the park, so the park service brought in a small pack of wolves. The population should decrease over the next few years. Question: Which population will decrease?

deer