The best source of lipids in your diet from the options provided is:
c) olive oil
Olive oil is primarily composed of fats (specifically monounsaturated fats) and is a well-known source of healthy lipids. The other options contain minimal to no fats: whole wheat bread primarily provides carbohydrates, green salad contains very little fat, and frozen ice pops are generally low in fats or may even contain none at all.