The adverb 'literally' is used for 'emphasis while not being literally true'.
In the given question, it emphasizes the high volume of music as being deafening, without causing any actual deafness, and hence option B is the correct answer.
The music from the loudspeakers was not 'intended to cause deafness', and therefore option A, which means 'in such a manner so as to get a desired result' is incorrect.
The adverb relatively is used to indicate 'comparison'. Since in the above question, the volume of the music is not being compared to any other sound, option C is incorrect.
Practically refers to realistic/pragmatic/matter of fact situations. In the question above, there is no reference to someone actually turning deaf. Hence, option D is also incorrect.