A Patient Has Been Diagnosed with Dementia Secondary to Cerebral

A patient has been diagnosed with dementia secondary to cerebral disease.The family members note the patient "has not been as sharp as he once was" and that he has developed urinary incontinence and a gait disturbance.Which pathophysiology can cause such symptoms?

A) Normal pressure hydrocephalus
B) Vitamin B₁₂ deficiency
C) Hepatic disease
D) Tuberculosis