A six-year-old female spayed golden retriever is presented for acute onset of flaccid jaw paralysis. The dog is unable to close her mouth, has difficulty eating and is drooling. There is no history of trauma. What is the most likely diagnosis?

A - Masticatory myositis
B - Facial nerve paralysis
C - Trigeminal neuritis
D - Myasthenia gravis
E - Meningoencephalitis