To P/F or not to P/F that is the Question

So, I have to decide by March 26th which class I am going to take a Pass/Fail in. Taking a Pass/Fail grade status for a class makes it so I just have to get a 70% or higher in the class and I will get a Pass. Getting a Passing grade doesn't affect my GPA on my transcript at all, it just says that I have fulfilled the requirement of the given class. So, I am trying to decide which class is going to be most difficult for me for the duration of the semester. I have narrowed my decision down to two classes: English Literature and Mathematic Geometry. On my first big paper for English I got a B+ and on my Geometry exam I got a 80%. Because of these results, I am leaning towards the P/F in Geometry, but the final exam for English makes me really nervous as I am not a literary scholar by any means. Hmmm.....what to do.....? 11 days left till I have to know for sure....