【单选题】

in the project environment, the individual ultimately responsible for quality control is:

a. the line workers who must strive "to do things right the first time" to avoid quality problems.
b. the company's quality control manager who must work with the project members to ensure the quality control program is effective.
c. the head of the production department who retains ultimate quality control responsibility for all the company's projects.
d. the project manager who has ultimate responsibility for the entire project.
e. the customer who must ensure that he is receiving a quality product from the vendor.