Option B.
Step-by-step explanation:
Descompose the denominator of each fraction into its corresponding prime factors. Then:
![2=2*1\\8=2*2*2=2^3\\10=2*5](/tpl/images/0308/7968/ad041.png)
Now you need to choose the commons a non-commons with the highest exponent. These are: 2³, 1 and 5.
Finally you need to multiply them to get that the Least common denominator of
is. Therefore, this is:
![LCD=2^3*1*5\\LCD=40](/tpl/images/0308/7968/6414e.png)
This matches with the option B.