Consider the following with respect to Probability distribution :

(A) In a given sample space not more than four random variables can be defined

(B) Mean expectation values is a parameter and not a statistic

(C) In a Gaussain distribution if only mean and mode are same it is said to be normally distributed

(D) Probability of 'r' success 'n' Bernoulli is $P(r)={^nC}_rq^rp^{n-r}$

(E) Variables enables us to study the variability of a random variable from the mean expectation

Choose the correct answer from the options given below :

(B) and (E) only