Massive Dynamic Corporation needs $200 million to expand its production and to develop new products. It has agreed to issue written pledges that it will repay a specified amount of money with interest on a particular day. Because it is uncertain it will have sufficient funds available if all of the pledges should become due on the same day, none of the pledges will be paid during the first 15 years. After 15 years, 10 percent of the pledges will mature each year until all of them are retired at the end of the 25th year. What are the pledges?

Registered bonds 

Term-loan agreements 

Serial bonds

Bond indentures 

Sinking bonds