The correct option is A praise
Taunt means provoke or challenge (someone) with insulting remarks. The opposite of taunt is praise, or express warm approval or admiration of. Hence, Option A is correct. Among the rest of the options, publicise means make (something) widely known, boost means help or encourage (something) to increase or improve, encourage means give support, confidence, or hope to (someone). These options do not express the intended antonym, hence incorrect.