What we need to check on the spark plug?

[vermi]

Here the spark plug of my Kymco with a 72cc kit.

To know if i running lean or rich what i need to check first?
(See Picture)
A, B or C???



I ask this question beacause a dealer said to me i running rich, the ring (A) was black!

[art]

  B and c are way lean!!!  Take a look at this    http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

[winginman]

Thanks for the link on the spark plugs.  Handy to have bookmarked.