I'm writing a text according to APA standards. The rule regarding serial commas states "Use a comma between elements (including before and and or) in a series of three or more items."
Does this also apply to gerunds, where their object follows after the list?
a) "the sharing, exchanging, distributing, and creating of knowledge"
b) "the sharing, exchanging, distributing and creating of knowledge"
I would instinctively go for option a), but a canonical answer/authoritative source would be great.