What does it mean if the probability is 1/6 that a 5 will be rolled on a number cube?

a.
there are 6 chances that a 5 will be rolled.

b.
a 1 will be rolled once in 6 rolls.

c.
if a number cube is rolled 6 times, a 5 will always be on top one time.

d.
there is 1 chance in 6 that a 5 will be rolled.