According to MLA Handbook, the mechanics of prose refers to technical questions that writers must follow. These include.

The correct option is: Spelling, punctuation, capitalization, style of numbering.

According to the MLA Handbook, the "mechanics of prose" refers to the technical rules and conventions governing the presentation of text. These conventions ensure clarity and consistency across scholarly writing.
Specifically, the mechanics of prose cover spelling (including word division and foreign words), punctuation, capitalization, and the style of numbering (such as when to use numerals versus spelling out numbers).

Other concepts like grammar and linguistics belong to general language rules, while content relates to the substance of the writing rather than its mechanical presentation. Therefore, the option containing spelling, punctuation, capitalization, and style of numbering is the accurate description according to MLA guidelines.