Difficulty level 600? You gotta be kidding me - Anyway I understand the arguments about (E) but shouldn't "When" refer to a specific time period. For e.g., see this excerpt from the SC grail book that says
On the GMAT, ‗where‘ will always refer to a specific location and ‗when‘ will always refer to a specific time period; else their use is wrong.
Correct: The town where I was born is known for its fishermen.
Correct: It was a historic event when, in 1947, India achieved independence.
Incorrect: When the price goes up, the demand falls down.
Incorrect: The Company where I work has gone bankrupt. (OG 12 – Q 12, 104)