Section 2.19 of the manual states that if font size and style are not specified by the organization for which you are writing (e.g., publisher, university), you have several different options of fonts that may be used. These include 11-point Calibri, 11-point Arial, 12-point Times New Roman, and other fonts.
However, it is important to make sure that you use the same font consistently throughout your work (pg. 44).
