The average weekly earnings of the plumbers in a city is [Mu=$750] with a standard deviation

The average weekly earnings of the plumbers in a city is [Mu=$750] with a standard deviation of [s=$40].  Assume that we select a random sample of [n=64 plumbers], what is the probability that the sample mean [x] will be greater than $740 or greater than $755?

a. 0.0228

b. 0.1587

c. 0.3413

d. 0.4772

e. None of the above answers is correct.