I will be flying with United Airlines.

a) Italicize (underline)
b) Quotation marks
c) Neither

B?

Soryr again, United Airlines should have been bolded

B is incorrect.

http://guidetogrammar.org/grammar/index2.htm
Check out the choices here, and let me know what you decide.

Then is this Neither then, because I put A too and that was wrong?

Yes, "neither" is correct.

To determine whether to use italics/underline or quotation marks when mentioning the name of an airline like United Airlines, you need to consider the style guide or specific formatting guidelines you are following. Different style guides have different rules for formatting airline names.

In general, if you are following the guidelines of a style guide such as the Associated Press (AP) style, airline names should be written in plain text without any special formatting. In this case, the answer would be option c) Neither.

However, if you are working on a project that requires a specific style or if you are following a different style guide such as the Chicago Manual of Style (CMS), you might need to use italics or underline. In that case, the answer could be option a) Italicize (underline).

Ultimately, it is important to refer to the specific style guide or formatting guidelines you are using to ensure accuracy and consistency in your writing.