Answer:
A. enduring institutional base within the Republican Party.
Step-by-step explanation:
The tea party was initially funded by members of the republican party who has a very conservative view on economics. They want to cut the tax rate to the lowest possible and make government spending that can be allocated to welfare to the minimum.
In terms of political spectrum, the tea party tend to be on the right to the alt-right side of the spectrum. Moderate republicans tend to support government welfare to a certain extend and can accept liberal views in general. But in term of social views, the tea party also considered to be very conservative.