.md
.rmd
.html
none of the mentioned
Answer is Right!
Answer is Wrong!
The correct answer is B. .rmd.
knitr is a R package that facilitates the production of dynamic documents. It can be used to create documents in a variety of formats, including HTML, PDF, and markdown. When knitr is used to create a document in markdown format, the output file will have the extension .rmd.
Option A is incorrect because .md is the extension for markdown files. Option C is incorrect because .html is the extension for HTML files. Option D is incorrect because it is not one of the possible extensions for knitr documents.