Which of the Following Is Not True for an Exponential $\lambda$

Multiple Choice

Which of the following is not true for an exponential distribution with parameter $\lambda$ ?

A) $\mu = 1 / \lambda$
B) $\sigma = 1 / \lambda$
C) The distribution is completely determined once the value of $\lambda$ is known.
D) The distribution is a two-parameter distribution, since the mean and standard deviation are equal.