No-brainer (noun)

A decision or action that requires little or no thought or consideration as it is obvious or easy to make.

Origin:

The phrase no-brainer is an informal term, it means a decision or action that requires little or no thought or consideration as it is obvious or easy to make.

Examples:

1. It was a no-brainer, of course, I'm going to take the job.
2. It was a no-brainer to invest in that company.
3. It's a no-brainer, we should take the deal.
4. The choice was a no-brainer, he had to pick the red one.
5. It was a no-brainer, he had to stop the car.