Which owuld likely be the least biased account for the December 7, 1941 attack on Pearl Harbor

the least biased account would be: a world history textbook’s account published in 2014

For starter, the story from the sides of all the people involved in the attack will be extremely biased, because both of them will tend to believe they're fighting for the right side.

A history textbook that's written decades later would most likely provide us with an objective view because ti's created after studying the perspective of both sides.