D, because of the arrows going both directions, you know part of it,

and then you just have to put in the values from the number line. The first arrow ends at zero with a bracket, and brackets mean the number is included. So now you have,
( - infinity, 0] ( x, infinity)
Then, your last value is at 1/2 with a parentheses, indicating it is not included. So, your final answer would be,
( - infinity, 0] ( 1/2 , infinity)
{infinity is always written with a parentheses in domain}