The circle represents +/- 2 degrees (total 4 degrees) course deviation. The left or right circumference of the circle represents 1 dot = 2 degrees.
In the diagram the QDM is displaced 4 degrees from the required track therefore the QDM is 146M.
The QDR is therefore 326M
Applying the Magnetic Variation of 4W the QTE is therefore 322T = Answer D.
Modern CDIs display simply 5 dots either side of centre.
At 2 degrees per dot the full scale deflection is at the 5th dot = 10 degrees.
Beyond that fifth dot Course Deviation is not measurable.