A 39-year-old pregnant woman with gestational diabetes mellitus complains of vulvar pruritus.Her exam is the vulva and vagina appear erythematous. The discharge is white, thick, adherent, and clumpy (curd-like) without odor.which is the most likely diagnosis?（   ）
A、Bacterial vaginosis
B、Candida vulvovaginitis
C、Urethritis 
D、Trichomoniasis