Studies have shown that acrolein, the main component of smoke produced by smoking, is a "chronic killer" for eye health, and hydroxytyrosol, an olive oil extract, can effectively reduce the damage caused by this "chronic killer" to the eyes. It was concluded that regular consumption of olive oil can keep smokers' eyes away from harm. If the following are true, the ones that support the above argument are:. ['Hydroxytyrosol is easily absorbed by the body.', 'Olive oil contains other substances that are beneficial to the human body.', 'People who eat olive oil have better eyesight than people who do n’t eat it often.', 'Smoke also contains other substances that are harmful to vision.']