The correct option is A always
Option A: 'Always' is an adverb of frequency. It indicates that some action is taking place 'all the time'. Hence option A is correct.
Option B: 'Not' is not an adverb of frequency. It's a tool used to convert a positive sentence to negative. It has no relation to time and hence, frequency. Hence B is incorrect.
Option C is incorrect because 'not' is not a frequency adverb.
Option D is incorrect because the answer lies in A.