All laboratory tests and imaging studies are normal. What is the most likely diagnosis of this patient?

A 32 year old woman who is recently divorced visits her physician for visual disturbances. The patient complains of trouble vision for 3 days. On examination, tunnel vision is detected along with marked weakness of planter flexion although the patient can walk on her tiptoes without any complaint. All laboratory tests and imaging studies are normal.
What is the most likely diagnosis of this patient?
A-Conversion disorder
B- Meningioma
C- Multiple sclerosis
D-Transient ischemic attack