The correct answer is A. take.
The sentence is in the simple present tense, which is used to talk about general truths or habits. In this case, the speaker is saying that it usually takes the person 20 minutes to get to work. This means that the action is repeated regularly, and there is no specific time or date being referred to.
The other options are incorrect because they are not in the simple present tense. Option B, is taking, is in the present progressive tense, which is used to talk about actions that are happening right now or that are happening over a period of time. Option C, have taken, is in the past participle form, which is used to form perfect tenses. Option D, is not taking, is in the negative form of the present tense, which is used to talk about actions that are not happening or that are not true.
In conclusion, the correct answer is A. take.