Which of the Following Statements Is True of the Standard $\mu$

Which of the following statements is true of the standard normal distribution,but not other normal probability distributions?

A) P(X<0) =0.5
B) it is symmetric
C) P(X<( $\mu$ _x-1) ) = P(X>( $\mu$ _x+1) )
D) it is often referred to as a "bell" curve