The table shows the number of calls received by each of five operators during each of 5 one-hour periods. For which operator was the standard deviation of the numbers of calls received during these 5 periods the least?
Choose the correct option.
A) Operator A: 3, 7, 7, 3, 4  B) Operator B: 4, 5, 5, 6, 5  C) Operator C: 8, 2, 5, 5, 6  D) Operator D: 6, 4, 4, 6, 6  E) Operator E: 3, 4, 5, 8, 7
Operator A: 3, 7, 7, 3, 4   it has 2 numbers right at the average, Operator A: 3, 7, 7, 3, 4 has none.
<result>A</result>
The table shows the number of calls received by each of five operators during each of 5 one-hour periods. For which operator was the standard deviation of the numbers of calls received during these 5 periods the least?