An organism not invading intact cornea-: (A) Gonococci, (B) C. diphtheriae, (C) Meningococci, (D) Pseudomonas
Answer is D. Following three pathogens can invade the intact corneal epithelium and produce ulceration:

Neisseria gonorrhoea,
corynebacterium diphtheriae and 
Neisseria meningitidis.