Answer:
An optional Call
Step-by-step explanation:
Callable Bond
Callable bond represents an instrument of debt where the issuer issues the instrument reserving the right to make a return of the principal of investors including the stoppage of interest payments before the date of maturity of the bond.
Organisations would usually issue bonds as callable when either to meet unexpected obligations like pay off other debts, fund expansions or when they sense that opportunities may arise in the future for them to get other forms of financing at lower interest rates.
For bonds to be callable the terms must be clearly stated in the bond's offering.
Optional Call
In optional call, the issuer reserves the right to call the bonds to take advantage of present circumstances such as significant drop in interest rates (as stated in the question). However, the terms detailed in the bond resolution will allow the bondholders to receive a premium to par as compensation for their loss of interest payments on the called bond.
Furthermore, a period of time must usually pass before the issuer can use the optional call.