Imagine you have a conversation with someone else e.g. your friend and he wants to ask you about something which it's answer is completely clear to you.
There is an idiom in my language which says:
It is like a painting that... [Meaning that everything is clear to you and the facts acknowledge that...]
In the Cambridge dictionary I found a possible equivalent for the meaning in my question:
Person A) Who do you think is better-looking, Jennifer Lopez or Jessica Alba?
Person B) That’s a complete no-brainier! Jessica Alba is much better-looking.
However, I doubt if it (the idiom "no-brainier") is the most clear to what I am looking for.
I need to know find out how an AE speaker would say it?