Answer:
B
Step-by-step explanation:
If the first roll is a 4, the possibilities to add less than 8 are that the second cube roll is 1, 2 or 3.
These are 3 different events out of 6 possilbe ones, which is 3 / 6 = 1 / 2; i.e. half of times.
Then the answer is the first option: 1 / 2