Hint: Verbs are action or doing words or a verb is a part of a sentence that tells what the subject performs. For example run, walk, eat, play etc. Verbs have three forms: First form of the verb, Second form of the verb and Third form of the verb. For example: write, wrote and written.
Now let us look into the options for the required answer
Option A) Assuage – is the correct answer because the verb 'assuage', which means to satisfy (an appetite or desire), best befits the given context and conveys the meaning in the sentence. Hence, option A is the correct answer.
Option B) Parch – is not an incorrect answer because the verb ‘parch’ means make or to become dry through intense heat does not fit in the sentence correctly. Hence, this is an incorrect answer.
Option C) Savor – is an incorrect answer because the meaning of the verb ‘savor’ is taste (good food or drink) and enjoy it to the full. However, savor does not go with the sentence because here in the sentence he is unable to satisfy his thirst. Hence, this is an incorrect answer.
Option D) Describe - is an incorrect answer because the meaning of verb describe is to narrate or to relate and here in the sentence nothing to relate or describe. Hence, incorrect answer.
Option E) Attenuate – is an incorrect option because the meaning of attenuate is effect or physical thickness. Such a verb is not appropriate in the sentence. Hence, this is an incorrect answer.
Hence the correct answer is option ‘A’.
Note: In such questions where verb is used it is very important to understand the meaning of the words and their best fit in the blank.