Stories about how people somehow know when they are being watched have been going around for centuries. However, few (1)________ have been made to study the phenomenon scientifically. Now, with the accomplishment of the largest ever research of the so-called staring effect, there is striking indication that this is a recognizable and (2)________ sixth sense. The research elaborates thousands of kids. For the research, they stood with their eyes covered and with their backs to other youngsters, who were told to either stare at them or look away. The outcomes constantly revealed that the kids who could not see were able to (3)________ when they were being stared at. In total of 14.000 experiments (4)________ globally, the teenagers (5)________ sensed when they were being watched almost 81% of the time. Điền vào số 3 A. sign B. discovery C. expose D. tell