FYI: The first time I got the sentence, there was only one "a". But the second time, I had two "a" and the word bank offered more words too. I screenshot, so it's not my mistake. Very weird.
Did you look up “rajin” in KBBI? “Rajin” is used when a person loves hardworking (on learning etc.) and is always energized. This adjective bears “proactive” nuance whereas I don’t find it in the word “disciplined”.