Which relation is a function? OA.
{(2, 3), (1, 5), (2, 7))
B. (-1, 5), (-2, 6), (-3, 7)
Oc. (11,9), (11, 5), (9, 3))
OD.
(3, 8), (0, 8), (3, -2)}

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?