First, note that [tex] \sqrt{x} [/tex] is always positive (except for x=0), so [tex] -\sqrt{x} [/tex] must be always negative.
Thus, the only plausible graphs are 1 and 3 since they are below the x-axis.
Now, [tex] \sqrt{x} [/tex] and [tex] -\sqrt{x} [/tex] are only defined for x≥0, because only for these x'es we can take the square root.
Note that the third graph has domain (-infinity, 0], so it is not the right one, while 1 is ok.
Answer: first graph
