An airline claims that 65% of its flights depart on time

An airline claims that 65% of its flights depart on time. A sample of 100 flights was examined and it was determined that 63% left on time. If the goal is to test whether less than 65% of the flights depart on time, what is the value of the critical test statistic at the 5% level of significance?

a.            t = -1.645

b.            t = -1.96

c.             z = -1.645

d.            z = -1.96