In which sentence is the word obstinate used correctly? They were going obstinate when we showed up late.
O He will obstinate them until they give up.
When the teacher attempted to discipline him, he was obstinate.
The obstinate car drives smoothly and easily.

Obstinate means stubborn. So replace ‘obstinate’ in each sentence with ‘stubborn’ and see which one makes the most sense:

They were going stubborn when we showed up late.
He will stubborn them until they give up.
When the teacher attempted to discipline him, he was stubborn.
The stubborn car drives smoothly and easily.

Hopefully, that makes it clearer!

What exactly do you need with? i will try and do my best to you