Answer:
"With each hour-and-a-half orbit of Earth, Glenn watched the sun rise and set."
Step-by-step explanation:
Friendship 7 made three orbits round the earth and this took a total of 4 hours 55 minutes. The orbital period in this case, is the time taken for Friendship 7 to complete an orbit round the earth. Since the total of three orbits took 4 hours 55 minutes, one orbit would take an hour and a half.
Therefore, the expression that would correctly how long it takes Friendship 7 to completely circle the earth, is the first sentence.