Choose the word closest in meaning to the word 'ARDENT'.

Ardent means showing strong enthusiasm or feeling, as in an ardent supporter, so 'passionate' is the match. 'Casual' and 'mild' suggest a lack of intensity, and 'wary' means cautious. The trap is to link 'ardent' with 'arduous', which means difficult. Think of the word in a sentence first, and then pick the option that could replace it without changing the meaning; watch out for the antonym placed among the options.