A rectangle’s length and width are 4 centimeters (cm) and 6 cm.

This problem tests area formulas and fraction application. First calculate the full area of the rectangle using the given formula: Area = length × width. Multiply 4 cm by 6 cm to get 24 cm². The question asks for one-half of the area, not the total area. Divide 24 by 2: 24 ÷ 2 = 12 cm². Therefore, option B is correct. Option C is the full area, not half. Option A results from subtracting instead of dividing. Option D represents an incorrect partial calculation. NEX geometry questions often require careful reading to determine whether the question asks for total area or a fraction of it.