Read Jao's essay and his intended revision. During World War II, pilots in the Royal Air Force had a problem. They did not have a good way to record Information or update their logs in
flight. There were no pens that worked well in the cramped and strained environment of the airplane cockpit. The standard fountain pens were too
sensitive to changing atmospheric pressure. Early ballpoint pens could not be used to write on vertical or overhead surfaces. Both kinds of pens
could be leaky
[1] Fortunately, two Hungarian war refugees, the Biro brothers, had a solution. [2] They had been able to solve the problems of previous
ballpoint pens. [3] Basically, if the ink used in ballpoint pens was good at drying quickly, it was too thick and caused the pen's ball to stick. [4] On the
other hand, If the ink flowed freely, it was smudgy like fountain pen ink and the ball could not keep the reserve ink from leaking out of the pen.
[5] Georg Biro, a chemist, solved the problem by using ink similar to that used in printing newspapers. [6] His brother Laszlo, a journalist, had given
him the key idea. [7] Quickly, the Royal Alr Force and the United States Army Air Corps adopted the new technology and a small problem was
solved. [8] The two brothers who had their lives in Budapest destroyed by the start of the war and who had fled across Europe finally ending up in
Buenos Aires, Argentina were able, in a small way, to aid in the war effort.
Jao wants to add this sentence to his essay to elaborate on the contribution of Georg's brother.
Laszlo Biro is actually most often remembered as the inventor of the ballpoint pen because he also invented the mechanism for the tip of the pen.
Where should Jao insert the additional sentence?
O 1. after sentence 2
O 2. after sentence 4
O 3. after sentence 6
04. after sentence 8