An injector molder produces plastic pens. The process is designed to produce pens with a mean weight of 0.250 grams. To investigate whether the injection molder is operating satisfactorily, 40 pens were randomly sample with a mean of 0.2525g. The population standard deviation is believed to be approximately 0.0022g. Find a 99% confidence interval for the population mean. Select one: O a. [.2521; .2529] O b. [.2514; .2536] O.c. [.2517; -2533] O d. [.2518; 2532] e. [.2516;2534]