Final answer:
The statement is false; in text formatting, it is possible to apply underline, bold, and italics simultaneously to text.
Step-by-step explanation:
The statement you have asked about, 'You can apply only one of these at a time: underline, bold, or italics,' is false.
In text formatting, it is possible to apply multiple styles to text simultaneously. For example, in many word processing programs, you can make text bold and italicized at the same time or bold and underlined. This allows for a variety of text presentations to emphasize different points or to denote different types of information, such as book titles, foreign words, or important concepts.