听力原文： At least four Muslim worshippers have died and some 50 others were wounded in a grenade attack on a mosque in Kashmir. Officials said the attack took place immediately after Friday prayers at the Chrar-e-Sharief shrine in Badgam district, 30 kilometers west of Srinagar. Some of the injured are in critical condition. There has been no claim of responsibility for the at-tack. How many casualties did the attack cause? A．39. B．15. C．50. D．54.