Quality control is best defined as:

a. ensuring that the project deliverables or end items would be acceptable to the customer
b. the process of ensuring that quality assurance is performed according to the quality plan to ensure conformance to specifications (set by the organization performing the project) and to eliminate the causes of specific problems
c. continuous improvement activities that contribute to the project management maturity of the organization and provide benefit to both future and current projects
d. the process of keeping track of design information and changes and ensuring that everyone involved with the project or its end product has the most current design information
e. Decisions regarding standards and specifications to be met

The correct answer is letter "B": the process of ensuring that quality assurance is performed according to the quality plan to ensure conformance to specifications (set by the organization performing the project) and to eliminate the causes of specific problems.

Explanation:

Quality control refers to the set of steps companies take to measure how good their product is intending to avoid problems at the moment of providing them to end-users. According to each good manufactured the company has guidelines established with the minimum standards that the product must meet.  

The most rigid quality control is, the higher the possibilities of offering a reliable product to consumers.

u = 30

continuing your method

= +

subtract from both sides

= - thus

= -

= ⇒ u = 30