For two perpendicular lines, the product of the slopes equal -1, such that

The main line's equation is given by

On comparing with the slope-intercept form of the equation of a line,

The slope is given as -2.
Hence, the slope of the second line will be

Next, we check the options to find which has a slope equal to 1/2.
OPTION 1: x - 2y = 6
Rewriting in the slope-intercept form, we have

Therefore, the slope of the line is 1/2.
Hence, the FIRST OPTION is correct.