A 24-year-old G3P1102 at 38 weeks with a complaint of leakage of fluid from the vagina. She reports good fetal movement, no vaginal bleeding,and no contractions. She is afebrile. Sterile speculum exam demonstrated a pool of fluid in the vagina which is nitrazine positive and shows ferning on glass slide exam. On exam, her cervix is 1 cm and long. Fetal heart rate(FHR)is reassuring, and no contractions are noted. What is the diagnosis?（ ）
选项：

A:In labor;
B:PPROM;
C:PROM ;
D:Placenta abuption;
E:Threatened labor