D is the answer to this question. Let us remember that the software engineer can type 100 lines of code every 10 minutes. So during the first 10 minutes, he creates 100 lines of code. He then takes a 5-minute break. Then he makes 100 lines of code again then takes another 5-minute break. At this point, 30 minutes have already passed.
Let us assume that the same thing will happen in the other half of the hour which means that he will be able to make 200 more lines of code. If you would add the 40 minutes that will be spent on doing lines of code, that will be 100+100+100+100 which will amount to 400.