I'm trying to get a typical Latex strikethrough with MathJax in an HTML export, i.e., \cancel{thing} puts line through "thing". This tells me how. But I don't know how to include this MathJax markup in an org file for HTML export. If I forego MathJax -- i.e., #+OPTIONS: tex:dvipng instead of #+OPTIONS: tex:t -- \cancel works, but I need to use MathJax. It doesn't look like org-html-mathjax-options is expandable. . . .