At the yesterday's meeting, he adopted a recalcitrant attitude.

Answer: Option B

Conciliatory : intended or likely to placate or pacify.
Obstinate : stubbornly refusing to change one's opinion or chosen course of action, despite attempts to persuade one to do so.
Sympathetic : feeling, showing, or expressing sympathy.
Courteous : polite, respectful, or considerate in manner.
Recalcitrant : having an obstinately uncooperative attitude towards authority or discipline.

Synonym of Recalcitrant is Obstinate