Following the theory, the X-A leg is the first leg of the price fall, then follow by the A-B leg up retracing 78.6%, then leg down to B-C leg retrace 38.2% - 88.6% and the final leg is C-D which normally price would go up to 127% or 161.8%.
if price follow as I drew, I would enter my long position from the low of C-D leg and take profit accordingly. Please note, this is not a financial advice