I would expect that "An Article in a Web Magazine" is probably the most appropriate MLA citation format.
Based on MLA Formatting and Style Guide, and considering Quora as a web magazine, I would say, in APA:
Author, A. A. (Year, Month Day of answer). Title of answer [Answer to question]. In Quora. URL of the question.
Note that the format for citing an answer on Quora is similar to citing a blog post or online forum post. If you cannot find all the information required for the citation, include as much information as possible and follow the APA guidelines for citing electronic sources.
What's your opinion?