Ok, here we have an probability problem:
So we are going to calculate first their occurrences separately and then their union.
Probability of rolls an even number: 1/2 (2.4.6)
Probability of rolls an odd number: 1/2 (1.3.5)
Probability of get first an even number and then an odd number:
The probability of get first an even number and then an odd number is 1/4.
Option A.