Asap four students did a survey to find the soda flavor sixth-grade students prefer. the table below shows the method each student used to conduct the survey:

student method
trey asked 100 students at random from his seventh-grade class what their favorite soda flavor is
jesse asked 100 sixth-grade students at random what their favorite soda flavor is
nita asked 100 eighth-grade students at random what their favorite soda flavor is
ruben asked 100 third-grade students at random what their favorite soda flavor is

which student's survey is most likely not biased?

trey
jesse
nita
ruben