Answer:
Unlikely
Explanation:
Let's go over the four terms and what they mean.
Likely: Greater than 50% (1/2) and less than 100% (1) chance
Certain: 100% (1) chance or more
Unlikely: Less than 50% (1/2) chance, greater than 0% (0) chance
Impossible: 0% (0) chance
Since 1/8 is less than 50% (also known as 1/2) but greater than 0% (also known as 0), the correct term is unlikely.