When six unbiased dice are rolled simultaneously, the probability of getting all distinct numbers (i.e., 1, 2, 3, 4, 5, and 6) is

When 6 unbiased six-sided dice are rolled simultaneously:

1. The total number of possible outcomes is:

2. The number of favorable outcomes where all dice show distinct numbers (a permutation of the set $\{1, 2, 3, 4, 5, 6\}$) is:

3. The required probability $P$ is:

Dividing both numerator and denominator by $24$:

Hence, the correct option is (B).