$$
\displaystyle {\binom{\displaystyle{a\over b}}{\displaystyle{c\over d}}}
\textstyle {\binom{\displaystyle{a\over b}}{\displaystyle{c\over d}}}
\scriptstyle {\binom{\displaystyle{a\over b}}{\displaystyle{c\over d}}}
\scriptscriptstyle {\binom{\displaystyle{a\over b}}{\displaystyle{c\over d}}}
$$
