37-year-old teacher is hospitalized with complaints of weakness, incoordination, dizziness, and loss of balance. The diagnosis is multiple sclerosis (MS). Which of the following signs and symptoms, discovered during the history and physical assessment, is typical of MS ？（）

A．Diplopia, history of increased fatigue, and decreased or absent deep tendon reflexes.

B．Flexor spasm, clonus, and negative Babinski’s reflex.

C．Blurred vision, intention tremor, and urinary hesitancy.

D．Hyperactive abdominal reflexes and history of unsteady gait and episodic paresthesia in both legs.

影响外源性化学物质分布的主要因素是（）

A.胃肠道内pH

B.血浆蛋白质水平

C.体内各种屏障

D.A、C正确

E.B、C正确