The correct answer is A) Open hopper. An open hopper barge is a type of river barge designed to carry bulk commodities such as coal, gravel, or other cargo that does not require weather protection. The "open hopper" refers to the barge's design, which features an open top or hopper that allows easy loading and unloading of the cargo. This type of barge is well-suited for transporting dry, granular materials along inland waterways. The other answer options are incorrect because: B) Single skin and C) Double skin refer to the construction of the barge's hull, not the design of the cargo hold, and D) Deck barge is a different type of barge used for carrying general cargo on the deck rather than in a hopper.