I try to use scrbook class, and play with basic options - **paper size**. I know that is based on KOMA script and for these reasons I should use package `typearea` instead package geometry. See MNWE:

```
\documentclass{scrbook}
\usepackage[paper=b4paper]{typearea}

\usepackage{lipsum}

\begin{document}
  \lipsum[2-8]
\end{document}

```

I got Latex error: Option clash for package typearea! So I try this

```
\documentclass[paper=b4paper]{scrbook}
%\usepackage[paper=b4paper]{typearea}

\usepackage{lipsum}

\begin{document}
  \lipsum[2-8]
\end{document}

```

This leads to Latex warning: Unused global option(s): [paper=b4paper]