The value "e" is a constant value, which is equal to approximately 2.72.
Since it is a value greater than 1, the fraction 1/e is a value between 0 and 1.
The expression e^-6 is the same as 1 / e^6.
e^6 is a value greater than 1, therefore 1 / e^6 is a value between 0 and 1.
The only option with a value between 0 and 1 is option D.