The correct answer is D. All of the above.
Debentures are a type of loan that a company can issue to raise money. They are considered to be a relatively safe investment because they have a fixed interest rate and a maturity date, which means that the investor knows exactly how much they will earn and when they will get their money back.
In addition, debenture-holders enjoy prior claim on the assets of the company over its shareholders in the event of liquidation. This means that if the company goes bankrupt, the debenture-holders will be paid first before the shareholders.
Finally, a trustee is appointed to preserve the interest of the debenture holders. This means that there is an independent person who is responsible for making sure that the company complies with its obligations to the debenture-holders.
All of these factors make debentures a more attractive investment than shares.