题目内容：
根据材料，回答问题。B
AC Milan star Kaka says a foot injury is still stopping him from returning to football. Hs hasnot played for 32 days. Kaka says he is in a lot of pain. "I hurt myself in an area that we always put pressure on. " Kaka once played for a year with a knee injury, but the 26-year-old said this is much worse.
British actress Emma used to spend more time filming than at school. But today she is readyto pay more attention to her studies. This 19-year-old girl will start at the Yale University in the au-tumn. "I always loved school. I just want to go back and find what else there is," she said.
Chinese 25-year-old sports star Liu Xiang returned to Shanghai in March. He had a successfulfoot operation in December in Houston, and spent the next three months there for recovery and basictraining. It is said that a group of doctors are ready to help with Liu's recovery.
Russian great tennis player Sharapova will not be playing in the MPS Group Championships,which begins in the US on Monday. Sharapova was missing the Sony Ericsson Open the week beforelast in Miami. She may continue training for the WTA Rome event at the beginning of May.
Liu Xiang's foot operation was successfully done in December in________ A．Miami
B．Rome
C．Houston
D．Shanghai
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