请问其他两个选项错在哪里？

问题如下：

There's a bond issued by national governments, unsecured obligations of the sovereign issuer and backed by their tax power. This kind of bond is most likely to be assorted:

选项：

A.

quasi-government bond.

B.

non-sovereign government bond.

C.

sovereign bond.

解释：

C is correct.

The national governments issue bonds in various types and amounts, which are referred to as sovereign bonds.

考点：债券种类

解析：国家政府发行各种类型和数额的债券，称为主权债券。