Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 34 to 40.

Aristotle was right when he said, "Happiness depends upon ourselves." Happiness is synthetic - you either create it, or you don't. Even when you accomplish something great, that high won't last. It won't make you happy on its own; you have to work to make and keep yourself happy. Supremely happy people have honed habits that maintain their happiness day in, day out. These habits require emotional intelligence. Indeed, happy people are highly intentional. If you want to follow in their footsteps, learn to incorporate the following habits into your repertoire.

Surround yourself with the right people. Happiness is contagious. Happiness spreads through people. Surrounding yourself with happy people builds confidence and stimulates creativity, and it's flat-out fun. Hanging around negative people has the opposite effect. They want people to join in their misery so that they can feel better about themselves. Think of it this way: If a person were smoking, would you sit there all afternoon inhaling their second hand smoke? You'd distance yourself, and you should do the same with negative people because their unhappiness is lethal to everyone around them. Proof in point, the famous Terman study from Stanford followed subjects for eight decades and found that being around unhappy people is linked to poorer health and a shorter life span.

Express gratitude. The real neural antidepressant is gratitude. Gratitude boosts levels of serotonin and dopamine - the brain's happy chemicals and the same chemicals targeted by antidepressant medications. The striking thing about gratitude is that it can work even when things aren't going well for you. That's because you don't actually have to feel spontaneous gratitude in order to produce chemical changes in your brain; you just have to force yourself to think about something in your life that you appreciate. This train of thought activates your brain to make you feel happier. Put a reminder on your calendar each day so that you'll be sure to take a brief moment to pause and appreciate.

Do things in person. Happy people let technology do their talking only when absolutely necessary. The human brain is wired for in-person interaction, so happy people jump at the chance to drive across town to see a friend or meet face-to-face because it makes them feel good.

The word "it" in paragraph 3 is closest in meaning to _______ . A. gratitude B. serotonin C. dopamine D. brain