The customer care manager at telecom operator, PhoneMe, has conducted a study to assess the customer loyalty. He has used the data set he recently collected and reached the following information: total loyalty score = 378.3, total variation = 47.6922, the benchmark he set = 7.25, standard error = 0.139521339. He reached a conclusion that the customer loyalty has significantly exceeded his expectation at 95% confidence level.

Based on above information, what was the sample size (rounded):

a.50

b.49

c.98

d.100