Step 1: The classic clinical sign asked here is the "inverted champagne bottle" leg, where the lower leg is narrowed and tight while the calf above bulges out.
Step 2: This shape results from lipodermatosclerosis (LDS), a fibrosing panniculitis of the skin and subcutaneous fat in the gaiter area. Chronic LDS shows induration and hyperpigmentation of one or both lower legs, producing the narrowed ankle and the bottle-neck contour.
Step 3: LDS is a manifestation of chronic venous insufficiency and is most common in middle-aged women. So the answer is option (c) lipodermatosclerosis.
Step 4: Varicose veins show dilated tortuous veins, DVT shows acute unilateral leg swelling, and venous ulceration is an open gaiter-area ulcer - none of these alone produce the inverted bottle shape.