Which of the following sentences is an opinion?

A．Four people in Jiangsu died in early April because of H7N9 bird flu infections.

B．China’s star swimmer Sun Yang won the first prize on April 1st at the National Swimming Championships.

C．People think Peng Liyuan, wife of President Xi Jinping, will draw great attention from people both at home and abroad.

D．It is reported that many college students have volunteered to serve in the 2014.Nanjing YOG.