How have the DUP's seats changed from 1998 to 2017?

The correct answer indicates that the Democratic Unionist Party (DUP) increased its number of seats from 20 to 28 between 1998 and 2017. This reflects a significant growth in support for the DUP during this period, illustrating changes in the political landscape of Northern Ireland, particularly in the context of shifting voter bases and electoral dynamics.

The DUP's rise in seats can be attributed to various factors, including the party's stance on key issues like Brexit, as well as its ability to adapt its messaging and appeal to a broader spectrum of unionist voters over the years. The increase in seats is also significant in the context of the Assembly elections, where gaining constituency seats is crucial for exerting influence within the devolved government.

Other options have seat counts that do not align with the actual electoral data. For instance, any range indicating fewer than 20 or more than 28 does not accurately reflect the developments within the party's representation and could lead to misunderstandings about the party's electoral success and its role in Northern Irish politics during that period.