Option 1 -> Creates a fragmented sentence starting with "steel structures" without proper context or definition.
Option 2 -> Forms a complete, logical sentence starting with the definition of Biorock, explaining the process of its formation through mineral accumulation on steel structures.
Option 3 -> Begins with "electro accumulation" without establishing what is being described, creating confusion.
Option 4 -> Lacks coherent flow and fails to properly connect the concept of Biorock with the process description.
Hence, Option 2: (D), (B), (A), (C) -> This arrangement creates the sentence: "Biorock is the name given to the substance formed by electro accumulation of minerals dissolved in seawater on steel structures that are lowered onto the sea bed and are connected to a power source." This provides a clear definition followed by a logical explanation of the formation process. -> correct