A student measures the time period of 100 oscillations of a simple pendulum four times. The data set is 90 s, 91 s, 95 s, and 92 s. If the minimum division in the measuring clock is 1 s, then the reported mean time should be: [Main 2016]
a. 92±1.8 s
b. 92±3 s
c. 92±1.5 s
d. 92±5.0 s