A seasonal index for a monthly series is about to be calculated on the basis of three years' accumulation of data. The three previous July values were 110, 150, and 130. The average demand over all months during the three-year time period was 190

What is the approximate seasonal index for July?
A) 0.487
B) 0.684
C) 1.462
D) 2.053
E) cannot be calculated with the information given

B