Answer:
Should Marston Manufacturing Company accept or reject the project?
Marston C Company should reject the project because its expected return is lower than Division H's cost of capital.
Since the divisions' risk is so different, and probably their projects are also very different, the company should use different costs of capital to accept of reject the projects based on each division's cost of capital.
Imagine another situation where Division L is evaluating a project that yields 10%. If they used the company's WACC, then they should reject the project, but if they used the division's cost of capital, then they should accept the project (in this case I would recommend accepting it).
Explanation:
Division H's risk = 14%
Division L's risk = 8%
WACC = 11%