Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35.

Stories about how people somehow know when they are being watched have been going around for years. However, few ______(31) have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and ______(32) sixth sense. The study involved hundreds of children. For the experiments, they sat with their eyes covered and with their backs to other children, who were told to either stare at them or look away. The results consistently showed that the children who could not see were able to ______(33) when they were being stared at. In a total of 18.000 trials carried ______(34) worldwide, the children ______(35) sensed when they were being watched almost 70% of the time.