"Equity Investments":common stock

B is correct. Accounting standards and reporting requirements that allow meaningful and timely financial disclosures reduce the costs of obtaining fundamental information and thereby allow analysts to form more accurate estimates of fundamental values. They support informationally efficient markets. 

A is incorrect. Allocational efficiency refers to making resources available where they are most valuable. 

C is incorrect. Operational efficiency relates to the costs of arranging trades, which can be reduced via organized exchanges, brokerages, securitization, clearing houses, and so forth.

A is correct. The put option feature facilitates raising capital because the shares are more appealing to investors. As such, it provides a benefit to the issuing company. It also helps investors limit their potential losses because they can sell the shares back to the issuing company if the market price falls below the pre-specified put price. Therefore, putable common shares are beneficial to both the issuing company and the investors. 

B is incorrect. Convertible preference shares are less volatile and less risky than the underlying common shares because the dividend payments are known and more stable.

C is incorrect. Investors owning a small number of common shares would prefer cumulative voting, not statutory voting. Cumulative voting allows the investor to cast all votes in favor of a single candidate thereby increasing the chance of having her preferred candidate elected.