The Federal Republic of Germany has a three-tier administrative structure. What is the lowest political level called?

EDITORIAL LEARNING AID

Why is this answer correct?

The lowest political level consists of the municipalities, that is towns and communes with their own right of self-government (Art. 28(2) GG). City councils (a) are municipal bodies or their members, district administrators (b) head the districts, and district offices (d) are administrative units without a political level of their own.

Municipality at the bottom, district in the middle, state and federation above.

This translation and explanation are editorial learning aids. The official German wording and answer key govern the examination.