He has ___ ulcer on his leg
He has ___ ulcer on his leg
Explanation
When the word begins with a vowel sound (a,e,i,o,u) then you should use 'an' as it sounds better and feels easier to say.
When the word begins with a vowel sound (a,e,i,o,u) then you should use 'an' as it sounds better and feels easier to say.