Answer:
Option C, They arise when polyunsaturated oils are hydrogenated.
Explanation:
Polyunsaturated oils which are partially hydrogenated consists of trans fat in large amount. Trans fat is not at all good for health. It raises the bad cholestrol (LDL) and decreases the good cholestrol (HDL). They are responsible for causing diabetes of type 2.
However, when Polyunsaturated oils are fully hydrogenated they do not contain any trans fat as they have converted into saturated fats such as stearic acid
But, overall Trans fatty acid arises only when polyunsaturated oils are hydrogenated (partially).
Thus, option C is correct.
