In which sentence is the word obstinance used correctly?

Question

If you can carry a suitcase that big, I am impressed by your obstinance.
If you can carry a suitcase that big, I am impressed by your obstinance .

The obstinance formed when a volcanic eruption superheated the sand on the beach and turned it to stone.
The obstinance formed when a volcanic eruption superheated the sand on the beach and turned it to stone.

Sheila's obstinance meant she refused to do her chores even after Dad told her she'd be grounded if she didn't.
Sheila's obstinance meant she refused to do her chores even after Dad told her she'd be grounded if she didn't.

George believes in obstinance when it came to eating candy, so he definitely didn't eat your chocolates.

If you can carry a suitcase that big, I am impressed by your obstinance.
If you can carry a suitcase that big, I am impressed by your obstinance .

The obstinance formed when a volcanic eruption superheated the sand on the beach and turned it to stone.
The obstinance formed when a volcanic eruption superheated the sand on the beach and turned it to stone.

Sheila's obstinance meant she refused to do her chores even after Dad told her she'd be grounded if she didn't.
Sheila's obstinance meant she refused to do her chores even after Dad told her she'd be grounded if she didn't.

George believes in obstinance when it came to eating candy, so he definitely didn't eat your chocolates.

Answer 1

The word "obstinance" appears to be used incorrectly in most of the sentences you've provided. However, the most correct usage of the intended word "obstinacy" (which means stubbornness) is in the sentence:

"Sheila's obstinance meant she refused to do her chores even after Dad told her she'd be grounded if she didn't."

While "obstinance" as a word doesn't appear in standard English references, the context suggests it relates to obstinacy. If "obstinance" was intended to mean "obstinacy," then this sentence conveys the correct meaning effectively.

The usage in the other sentences is incorrect either due to the context or because they use "obstinance" incorrectly regarding its meaning.