The process in which hydrogen is introduced to vegetable oils to make them saturated is known as

Hydrogenation of vegetable oils and animal fats is a standard industrial procedure. The more saturated a fat is, the longer its shelf-life. Why? Because a site of unsaturation, an olefinic bond, is potentially a reactive site that can be oxidized.

Of course, these days we are sold on the benefits of unsaturated fats. A priori, an unsaturated fat will yield less energy upon combustion, and the C=C double bond is harder to metabolize than C−H bonds.

the correct answer is d