What is the name of Germany's current head of state?

EDITORIAL LEARNING AID

Why is this answer correct?

The head of state is the Federal President; Frank-Walter Steinmeier has held the office since 2017 and was re-elected in 2022. Bärbel Bas (b) was President of the Bundestag, Bodo Ramelow (c) was Minister-President of Thuringia, and Joachim Gauck (d) was Federal President from 2012 to 2017.

Federal President and head of state: Frank-Walter Steinmeier.

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