Answer:
a) Bonds Payable.
Explanation:
Since there is an issue of bonds as against cash, which need to be paid back in future, amount received will be credited to bonds payable.
Further the purpose of bonds will always be to acquire a capital asset as bonds are issued for long term finance generally, therefore, the bonds will be credited as bonds payable, rather than capital contributions.
Though a general note in notes to account can be added clearly specifying the purpose of issue of bonds.
a) Bonds Payable.
