Replying to Stats/Operations hwmk help

I have no idea how to find the proportion for question c, any help would be greatly appreciated
C-Spec, Inc., is attempting to determine whether an existing machine is capable of milling an engine part that has a key  specification of 4 ± .003 inches.  After a trial run on this machine, C-Spec has determined that the machine has a standard deviation of .002 inch. (a) Calculate the process capability for this machine.

(b) Should C-Spec use this machine to produce this part?  Why or why not? (c) What proportion of items will meet specifications on this machine?