Fat contains 9 kcal per gram, whereas carbohydrates and protein only contain 4 kcal per gram.
Triglycerides or fats are composed of one molecule of glycerol and joined via ester bonds with three molecules of fatty acids. Fatty acids are long chains of carbon and hydrogen usually between 14-24 carbons long. Due to the abundance of C and H, fatty acids are very hydrophobic and are not very soluble in water.
Fatty acids come in two major types, saturated and unsaturated. Saturated means that they have no double bonds. Unsaturated means that it contains double bonds. Generally, saturated fats (butter) have a high melting point so that they are a solid at room temperature. Unsaturated fats have a lower melting point and are a liquid at room temperature. Margarine is made by hydrogenating (adding H) to unsaturated vegetable oils increasing the amount of saturation and thus, the melting point (so it will be a solid).
Answer is option B i.e. "9 Kcal/g or 38 KJ/g" A calorie is a unit of energy that measures how much energy food provides to the body. The body needs calories to function properly. Fats are nutrients in food that the body uses to build cell membranes, nerve tissue (like the brain), and hormones. A gram of fat has about 9 calories, while a gram of carbohydrate or protein has about 4 calories.