To help students know about their sleeping habits, No. 7 Middle School made a survey among 150 students in Grade Nine. According to the chart below, _____ students can sleep at least 8 hours each night if they get up at 6 a. m.
 

Time to sleep	Before 10 p. m.	At 10 p.m.	Between 11 and 12 p. m.	After 12 p. m.
Percentage(百分比)	14%	26%	43%	17%

A、twenty-one

B、sixty

C、thirty-nine