A patient present with sudden b/l loss of vision with loss of light perception.The loss is more on right side.pupillary reflex, optokinetic nystagmus are present.Patient can not touch his fingers on closing his right eye.What is diagnosis ?

• A. Optic neuritis
• B. Anterior ischaemic optic neuropathy
• C. CMV retinitis
• D. Functional vision loss