First solve for the trig function 'cot'

Next take the sqrt of both sides (include plus/minus)

Now take reciprocal of both sides, this will change trig function to 'tan'
(cot = 1/tan)

Finally use the unit circle or inverse tan on your calculator to find x.
There will be 4 solutions, one for each quadrant.
When using the Internet to conduct consumer research, be sure to use reliable websites, verify sources and know the purpose. So the answer is letter D. All of these.
Is there a picture to go with this problem?