Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answers for each of the questions from 9 to 12.

A few decades ago, professional footballers spent their nights partying. Now, they are much more aware of the benefits of a good night’s sleep.

In 2011, sleep specialist Cheri Mah discovered that increasing sleep to 8-10 hours per night massively increased the speed and shot accuracy of basketball players. Other research shows that a single night of inadequate sleep can increase the risk of injury, and 64 hours of bad sleep reduces strength, power and balance, and can even cause the body to eat its own muscles! Consequently, managers started trying to improve their players’ sleep. Southampton Football Club’s manager Alek Gross forbade his players from consuming caffeine, sugar or fatty foods, which prevent sleep, in the evenings. Instead, they were given milky protein drinks which made them sleepy.

Now, many teams and players are trying to improve their sleep patterns, using various means. Manchester City player Sergio Aguero, for example, was finding it hard to sleep because his muscular body prevented his legs from closing when he lay on his side. He got a new mattress which matched his height and weight, thus keeping his neck and back aligned in the night. Meanwhile, James Milner from Manchester City found it hard to sleep after evening games. As a result, he was too tired to train the following morning. Setting a routine with a late bedtime, early rise and afternoon nap helped to fix this problem. Since these interventions are cheap and effective, even the less well-known teams can benefit.

A. that B. what C. who D. which