"我不同意这个决定。"

Translation: I don't agree with this decision.

[CalvinC.3]

this choice?

[jamesjiao]

You usually use 'decision' in a work context.

[roylao]

I said "I do not agree to this decision." and it was wrong

[James550591]

"agree to" is a phrasal verb and it is perfectly fine to be used here for
"I don't agree to this decision"

"agree with" is generally used with someone
"I don't agree with him/her"

I will inform Duolingo about this.