This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
A man with Pancoast tumor developed Horner's syndrome. All of the following are the features of Horner's syndrome, EXCEPT: 
Select and explain. 
A. Ptosis and Miosis in ipsilateral eye, B. Anhidrosis of ipsilateral face, C. Heterochromia irides, D. Apparent exophthalmos
D: Apparent exophthalmos
Answer: D: Apparent exophthalmos 
Explanation: Horner's syndrome consists of unilateral enophthalmos, ptosis, miosis, and loss of sweating over the ipsilateral half of the face or forehead (anhidrosis). It is caused by ipsilateral involvement of the sympathetic pathways in the carotid plexus, the cervical sympathetic chain, the upper thoracic cord, or the brain stem. Melanocyte maturation in the iris depends on sympathetic innervation; thus, a less pigmented (bluer) iris occurs in congenital or longstanding acquired Horner's syndrome. Ref: Riordan-Eva P., Hoyt W.F. (2011). Chapter 14. Neuro-Ophthalmology. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e.