The correct answer is option 2) i.e. She is admirably bitter about the lack of awards she has accumulated. Explanation: Let us look at each and every sentence separately.
Statement (I): In the given sentence, the word 'bitter' is used as an adverb which means to an intense or severe degree. The adverb 'bitter' is modifying the adjective 'cold'. Hence, the use of the word 'bitter' as an adverb in this sentence is appropriate.
Sentence (II): In the given sentence, the word 'bitter' is used as an adjective which means having or showing deep-seated resentment. But from the context of the sentence, the use of the word 'bitter' is inappropriate as the sentence is stating something opposite to the meaning of the word 'bitter', instead of the word 'bitter', its antonym 'unbitter' should be used as the appropriate word here.Correct sentence: She is admirably unbitter about the lack of awards she has accumulated.
Sentence (III): In the given sentence, the word 'bitter' is used as an adjective which means hard to accept or bear especially emotionally. The adjective 'bitter' is modifying the noun 'disappointment'. Hence, the use of the word 'bitter' as an adjective in this sentence is appropriate.
Statement (IV): In the given sentence, the word 'bitter' is used as an adjective which means difficult to endure. The adjective 'bitter' is modifying the noun 'lesson'. Hence, the use of the word 'bitter' as an adjective in this sentence is appropriate.