Which of the Following Is Not a Characteristic of a Probability

Multiple Choice

Which of the following is not a characteristic of a probability density function f(x) ?

A) f(x) ≥ 0 for all values of x.
B) f(x) is symmetric around the mean.
C) The area under f(x) over all values of x equals one.
D) f(x) becomes zero or approaches zero if x increases to +infinity or decreases to -infinity.