Question: who becomes chief resident on grey's anatomy season 7
[{'answer': 'Kepner', 'provenance': [{'wikipedia_id': '27660054', 'title': 'April Kepner', 'start_paragraph_id': 0, 'start_character': 6, 'end_paragraph_id': 0, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'April Kepner M.D.', 'provenance': [{'wikipedia_id': '27660054', 'title': 'April Kepner', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '27660054', 'title': 'April Kepner', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 991, 'bleu_score': 0.988919240064389, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14685744115398432224}, 'section': 'Section::::Storylines.\n'}]}, {'provenance': [{'wikipedia_id': '27660054', 'title': 'April Kepner', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 897, 'bleu_score': 0.6510022938286201, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14685744115398432224}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '27660054', 'title': 'April Kepner', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ["The character was originally set to appear in two episodes but Drew's contract was extended to the remainder of the sixth season, with her becoming a series regular in the seventh season. The character's main storylines involved her professional struggles, her religious beliefs, and her relationship with her best friend and now ex-husband Jackson Avery.", 'April Kepner M.D., is a fictional character from the ABC \'s hit medical drama "Grey\'s Anatomy". The character was created by series producer Shonda Rhimes and is portrayed by actress Sarah Drew. She was introduced in the episode "Invasion" as a surgical resident from Mercy West Hospital who joins the staff at Seattle Grace Mercy West after the two hospitals merge to compensate for the absence of some of the central cast members, and was created to be disliked by her colleagues. The character was originally set to appear in two episodes but Drew\'s contract was extended to the remainder of the sixth season, with her becoming a series regular in the seventh season.', 'April Kepner M.D., is a fictional character from the ABC \'s hit medical drama "Grey\'s Anatomy". The character was created by series producer Shonda Rhimes and is portrayed by actress Sarah Drew. She was introduced in the episode "Invasion" as a surgical resident from Mercy West Hospital who joins the staff at Seattle Grace Mercy West after the two hospitals merge to compensate for the absence of some of the central cast members, a']}}]}, {'provenance': [{'wikipedia_id': '27660054', 'title': 'April Kepner', 'section': 'Section::::Development.:Relationships.\n', 'start_paragraph_id': 23, 'end_paragraph_id': 23, 'meta': {'evidence_span': ['Kepner entertained several relationships throughout her time on "Grey\'s Anatomy". In her early appearances, she is introduced as the best friend and roommate of her fellow Mercy West resident, Reed Adamson. In the season six finale, when Reed is tragically murdered by Gary Clark during the shooting, April is the first to find her when she trips over her dead body. In season seven April forms a friendship with Meredith Grey and she eventually moves into her house.', 'But not April. April\'s really pretty much done nothing. She\'s completely untouched." Kepner entertained several relationships throughout her time on "Grey\'s Anatomy". In her early appearances, she is introduced as the best friend and roommate of her fellow Mercy West resident, Reed Adamson. In the season six finale, when Reed is tragically murdered by Gary Clark during the shooting, April is the first to find her when she trips over her dead body. In season seven April forms a friendship with Meredith Grey and she eventually moves into her house. Ellen Pompeo offered regarding their bond:', 'But not April. April\'s really pretty much done nothing. She\'s completely untouched." Kepner entertained several relationships throughout her time on "Grey\'s Anatomy". In her early appearances, she is introduced as the best friend and roommate of her fellow Mercy West resident, Reed Adamson. In the season six finale, when Reed is tragically murdered by Gary Clark during the shooting, April is the first to find her when she trips over her dead body. In season seven April forms a friendship with Meredith Grey and she eventually moves into her house. Ellen Pompeo offered regarding their bond: "Meredith will accept April in order to get the audience to accept her," and Drew further explained: "She\'s being plugged into the community. Meredith has really taken her under her wing, is really looking out for her. Having Meredith come around to April helps the audience come around to April."']}}]}]