D. The social context of the 1960's discouraged innovation and exploration because people were afraid of new technologies and feared being overrun by space aliens.
Simple. I assume the ones going to the middle school are currently in 5th grade at the elementary school. You have 126 coming into the middle school from each school. You need to multiply 126 by 4. You get 504. There will be 504 new students at the middle school.
