<prompt> Xerophthalmia Grade X-3A -Corneal xerosisBitot spotCorneal ulcer involving less than 13 of corneal surfaceCorneal ulcer involving more than 13 of corneal surface  <response>: Ans. is c i.e., Corneal ulcer involving less than 13 of corneal surface o WHO classification of xerophthalmiaXN Night blindnessXIA Conjunctival xerosisXIB Bitots spotsX2 Corneal xerosisX3A Corneal ulcerationkeratomalacia affecting less than one-third corneal surfaceX3B Corneal ulcerationkeratomalacia affecting more than one-third corneal surfaceXS Corneal scar due to xerophthalmiaXF Xerophthalmic fundus 