The lesion shown here developed in a 57-year-old woman after she bumped her leg against a coffee table. She had had chronic discoloration in the area for many years before the ulcer formed. What type of ulcer is this?
a. Ischemic ulcer
b. Arteriolar (hypertensive) ulcer
c. Neurotrophic ulcer
d. Venous insufficiency ulcer
e. Pressure ulcer