Answer: All of the above
Explanation:
A company should endeavour to be socially responsible if it will result in any of the listed circumstances as they are all benefits.
If this would increase the company's competitive advantage it should be embarked on as it would lead to the company having a better position in the market. It can also reduce the cost to the company of reputation damaging incidents.
A company having improved efficiency and workforce retention is a good company and if socially responsible actions will bring that, the company should do it. And with the purpose of a company being to maximise shareholder value, a company should definitely engage in socially responsible actions if there is a high correlation between CSR and stock price.