What does it mean to get an "I" (incomplete)?

Hi everyone,

It’s finals week here at UCLA. This is my second to last quarter (I’m graduating over the summer), and have a 3.92 here. I’m having a rough time finishing my work for one of my finals–it’s a final research paper. I have a C+ in the class, but the professor told me that if I get an A on the final, I’ll get an A in the class. The paper is due in two days, but I don’t know if I can finish it. He offered to let me take an “I” and turn it in over the summer. I know I can pull an “A” if I do that. Is it worth it, or should I push as hard as I can to turn it in on time on Tuesday?

I’m applying to top law schools this fall, and am worried it’d hurt my chances. I haven’t taken the LSAT yet, but based off practices, I’m expecting a 170+. What do you guys think? Is it better to take an “A” with an “I”, or should I turn it in on Tuesday and 50/50 get either an “A” or an “A-”? It’s a quarter 5 unit course.