Who is called the "Chancellor of German Unity"?

EDITORIAL LEARNING AID

Why is this answer correct?

Helmut Kohl was Federal Chancellor from 1982 to 1998 and shaped the reunification of 1990, which is why he is known as the "Chancellor of Unity". Gerhard Schröder and Helmut Schmidt were chancellors in other periods, and Konrad Adenauer was the first Federal Chancellor.

Kohl = unity in 1990; Adenauer = first chancellor.

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