The correct answer is A. have been.
The sentence is in the present perfect continuous tense. This tense is used to talk about an action that started in the past and is still happening now. In this case, the action is “white washing my house”. The speaker has been white washing the house since morning, so they are feeling tired.
The other options are not correct because they do not express the idea that the action started in the past and is still happening now. Option B, has been, is in the simple present perfect tense. This tense is used to talk about an action that started in the past and is finished now. Option C, will be, is in the simple future tense. This tense is used to talk about an action that will happen in the future. Option D, will have been, is in the future perfect tense. This tense is used to talk about an action that will be finished in the future.
Here are some examples of how the present perfect continuous tense can be used:
- I have been working on this project for hours.
- She has been waiting for you for ages.
- We have been playing football since we were kids.
- They have been studying for the test all week.