The correct answer is A) .27 foot. The reduction in GM (metacentric height) due to free surface effect can be calculated using the formula: Reduction in GM = (IT / ∇), where IT is the moment of inertia of the free surface and ∇ is the vessel's displacement. In this case, the cargo hold is divided into two tanks, each 35 feet long and 20 feet wide, and half-filled with seawater. The moment of inertia of the free surface (IT) can be calculated as IT = (2 x 35 x 20^3) / 12 = 46,667 ft^4. With a vessel displacement of 5,000 tons, the reduction in GM is calculated as .27 foot, which matches the correct answer A. The other options are incorrect because they do not accurately reflect the reduction in GM based on the given information.