What power does the Northern Ireland Assembly have concerning legislation?

The Northern Ireland Assembly has significant legislative powers, particularly allowing it to propose, amend, and reject laws that are specific to devolved matters in Northern Ireland. This authority is established under the constitutional framework set out by the Northern Ireland Act 1998, which created the Assembly following the Good Friday Agreement.

The Assembly can legislate on a wide range of issues, including education, health, and transport, thereby providing a degree of regional autonomy. This means that the Assembly is not just a rubber-stamp body but plays an active role in shaping the legislative agenda according to the needs and preferences of the people in Northern Ireland. The ability to amend legislation ensures that the Assembly can respond flexibly to the issues that affect its constituents.

In contrast, the other options misrepresent the Assembly's authority. The Assembly’s role is not limited to merely rejecting proposed laws, nor does it lack any power over legislation. Additionally, while it is true that the Assembly can propose laws, it does so within the framework of devolved powers, rather than proposing laws directly to the UK Parliament.整体上，选B是对北爱尔兰议会在立法方面实际权力的准确反映。