Spacing Issues with Use of Abbrevs Package

Question

Consider the code:

\documentclass[12pt]{book}
\usepackage{abbrevs}
\begin{document}
By 2100 \BC, almost universal corruption prevailed.
\end{document}

which produces

QUESTION: How may I adjust (reduce) the horizontal space between 2100 and B.C.; as well as reduce the gap between B.C. and the comma?

Thank you.