A catchment has eight raingauge stations. In a year, the annual rainfall recorded by the gauges (in cm) are 93.8,106.5,170.6,138.7,87.8,156.2,180.9 and $110.3 .$ For a $10 \%$ error in the estimation of the mean rainfall, the optimum number of stations in the catchment is
(A) 4
(B) 6
(C) 8
(D) 10
A catchment has eight raingauge stations. In a year, the annual rainfall recorded by the gauges (in cm) are 93.8,106.5,170.6,138.7,87.8,156.2,180.9 and $110.3 .$ For a $10 \%$ error in the estimation of the mean rainfall, the optimum number of stations in the catchment is
(A) 4
(B) 6
(C) 8
(D) 10