Answer:
a. Senior mortgage bonds b. Debentures c. Subordinated debentures
Step-by-step explanation:
A mortgage bond is a financial instrument which is backed by some real assets. These assets can be sold to cover the cost in case of default. Senior mortgage bonds are the first to be paid in case of bankruptcy.
Debentures are financial tool used for long term borrowing by corporations. They are not backed by any specific assets but by credit worthiness of the firm itself.
Subordinated debentures are the last to be paid off in case of bankruptcy and thus carries highest risk. However they also provide highest interest.