Google Apps: How do I remove Yahoo as my default search engine in Safari?

I am a user of the latest Mac system. My default browser is Safari.

For two weeks, when you search for something in the address bar, it is redirected to "Yahoo search engine"

How to check the pattern "Safari> Preferences> Search> Search engine"

I can see that my default engine is still Google (Google is the default engine that I like)

But still, if I look for something in the address bar, "it is redirected in Yahoo", not in Google and the results of the search are not optimal, as often happens with Google.

Can someone help remove or delete Yahoo as my default search engine?

It is behaving like a virus.

Any help or comment is welcome.