Identify the sentences that contain only one example of logos. 9 out of 10 professionals rate our site as user-friendly. should you need assistance, 300 tech-support workers are on hand, so you will never be placed on hold. we guarantee excellent customer service—all orders are right, or they're free. do you feel unappreciated by your boss? our low prices and high quality make gizmotry and gadgetry the world's best place to shop for gizmos and gadgets. we will continue to live up to our fine reputation.

The sentences that contain only one exmple of logos are:

9 out of 10 professionals rate our site as user-friendly.

Should you need assistance, 300 tech-support workers are on hand, so you will never be placed on hold.

We guarantee excellent customer service—all orders are right, or they're free.

Explanation:

Logos is a greek rhetorical element that is used to persuade the reader by providing data or establishing logical associations. In other words, they use show objective facts that have strong elements of evidence to be accepted as correct. In all of our options, the data provided is strong enough to show they are correct. 9 out of 10 makes the first one an example of logos. In the second one, the fact that you will be never be placed on hold because we have 300 tech-support workers convinces you of been right. The fact that makes the third convincing is that the order is right or free. The gadget should have been good but we are not certain that their quality and price are the best combo in the world to make that claim valid.

because each is self-sufficient.  

answer: may i ask who shelly is?