A 35 years old mother of two children is suffering from amenorrhea for last twelve months.She has history of failure of lactation following 2nd delivery but remained asymptomatic thereafter.Skull X-ray shows 'Empty sella'.Most likely diagnosis is:

• A. Pituitary tumor
• B. Menopause
• C. Intraductal papilloma of breast
• D. Sheehan's syndrome