Which user characteristic may NOT be used to change keyword bids in Google Ads?:
- ad preference
- device
- time of day
- location
or
Which user characteristic may NOT be used to change keyword bids in AdWords?:
- ad preference
- device
- time of day
- location
Explanation:
It comes under the bid adjustment. Bid adjustments allow you to show your ads more or less frequently based on where, when, and how people search. For example, sometimes a click is worth more to you if it comes from a smartphone, at a certain time of day, or from a specific location.
Read more here: https://support.google.com/adwords/answer/2732132