Answer: D. 40%
Explanation: Each of the three main biological macromolecules within our diet are worth a specific amount of calories per gram. Each gram of carbohydrate is worth 4 calories. Each gram of protein is also worth 4 calories. Each gram of fat is worth 9 calories.
Using this information, we can calculate the amount of calories 240 grams of carbohydrates are worth by multiply 240 by 4 since there are 4 calories per gram. 240 x 4 yields 960, so 240 grams of carbohydrates are worth 960 calories.
Next, we simply divide 960 calories by 2400 calories. Since we're trying to figure out the percentage of the daily calories that carbohydrates make up, we divide the number of calories provided by carbohydrates by the total amount of calories in a daily diet. [tex]\frac{960}{2400}[/tex] yields 0.4. To convert this to percentages, we simply multiply 0.4 by 100 and add a percentage sign.
Therefore, the carbohydrates make up 40% of daily caloric intake, thus making choice D the correct answer.