A quality analyst wants to construct a control chart for identifying whether four machines, all producing the same product, are under control with regard to a particular quality attribute. Accordingly, she inspected 1000 units of output from each machine, with the following results: machine 1 produced 45 defectives, machine 2 had 68 defectives, machine 3 produced 32 defectives, and machine 4 had 39 defects. For the upper and lower control limits of .062 and .034, which machine(s), if any, appear(s) to be out of control for proportion of defectives?
a. Machines 1 and 2.
b. Machines 1 and 3.
c. Machines 2 and 4.
d. Machines 3 and 4.
e. None of the above.