In the case where your monitor type (which is standard) is not offered by the list of types, choose another monitor in terms of the characteristics given by the technical instructions or information supplied by the vendor. At worst, choose one which has the most similar characteristics to yours. In general, the choice of monitor allowing 1024x768 resolution in non-interlaced mode at 60 Hz suits the majority of modern monitors. If you own a high quality monitor, choose more advanced characteristics.
As for the choice of vertical refresh rate, choose 50-90 Hz for a standard monitor.
ATTENTION: do not choose specialised characteristics, particularly characteristics which are superior to those for which your monitor was designed as they may damage or even destroy your hardware! Mandrakesoft/Linux-Mandrake cannot accept responsibility for any such accident.