A recent and popular self-help book wryly notes that if adolescence was not so painful, it would have a droll comedic aspect, at least in retrospect.
A) was not so painful, it
B) was not so painful, they
C) were not so painful, they
D) were not so painful, it
E) were not so painful, being one
I narrowed this down to (D) and (E), knowing that the subjunctive mood calls for "were." In deciding between the two, I ended up incorrectly choosing (E) because I felt that the "it" pronoun does not have a clear referent. I thought the "it" could refer to the book -or- adolescence.
Can someone help explain why this is not a pronoun error?
Thanks in advance for your help/feedback.