Final answer:
The correct option is A). Scleroderma is a condition characterized by the thickening and hardening of the skin due to new collagen formation.
Step-by-step explanation:
The thickening and hardening of the skin caused by new collagen formation is called scleroderma. This condition is characterized by the excessive production of collagen, leading to hard, tightened skin. Though other conditions like psoriasis, systemic lupus erythematosus, and dermatomyositis also affect the skin, they have different underlying mechanisms and symptoms. Psoriasis, for example, is known for patches of thick, red skin with silvery scales and is associated with an interplay between keratinocytes, dendritic cells, and T cells. Systemic lupus erythematosus is an autoimmune disorder affecting multiple systems. Unlike scleroderma, which specifically results in thickened skin due to collagen overproduction, these conditions present differing patterns of skin involvement.