Step 1: The question asks which of the listed causes shows the classic ulcer morphology in the esophagus. The contrast intended is between viral causes and a large linear ulcer.
Step 2: CMV oesophagitis (the oesophagitis option) classically produces a single, large, shallow, linear or longitudinal ulcer.
Step 3: This is opposed to herpes simplex esophagitis, which gives multiple small vesicular, punched-out, well-circumscribed ulcers. So per the key the answer is Oesophagitis (option c).
Step 4: Candida causes whitish plaques and pseudomembranes rather than discrete punched-out ulcers, so it is not the intended answer.