The correct answer is that the variable does have a binomial distribution; P(success)=0.5; the number of trials is 5.
This is binomial because it has a fixed number of trials, the trials are independent of each other, the probability of success is constant from trial to trial, and there are only 2 outcomes.
Since success is getting an even number, and there are 3 even numbers out of 6, P(success)=3/6=0.5.
There are 5 trials because you are rolling the cube 5 times.
