For group "a" shares if the graph is falling down check past 10-20 yrs history of graph, if it has performed well before ,then don't sell.
For group "b" & "c" if the graph is falling down check past history, even if it has performed well don't buy.
For group "a" if graph is rising up and past performance is good then don't sell.
For group "b" and "c" even if graph is rising and past performance is good then also don't buy.
