The correct answer is: D. have been getting/consider
The sentence is about a situation that has been happening for a while, and is still happening. The speaker is saying that the conditions in their office have been getting worse and worse, and that they have been considering quitting their job and looking for a new one.
The verb “have been getting” is used to describe a situation that has been happening for a while, and is still happening. The verb “consider” is used to describe the act of thinking about something carefully.
The other options are incorrect because they do not accurately describe the situation. Option A, “have got/was considering,” is incorrect because the speaker is saying that they have been considering quitting their job, not that they were considering it in the past. Option B, “was getting/am considering,” is incorrect because the speaker is saying that the conditions in their office have been getting worse, not that they were getting worse in the past. Option C, “are getting/have considered,” is incorrect because the speaker is saying that they have been considering quitting their job, not that they have considered it. Option E, “get/considere,” is incorrect because the speaker is saying that they have been considering quitting their job, not that they are considering it.