Rock Identification

The most ordinary rocks are the most difficult to id.
First--Your pitcures aren't really very good to display the rocks bedding or dtructure features. Also they are mostly unbroken and mostly covered with lichens . This hides their internal structure so. Anything I give you is a guess and a general one at that

A-looks like a hexagonal (columnar) jointed piece of an igneous rock. OR ELSE, its a red sandstone. I cant really tell from thepicture. The six sided feature it makes as it lays there, is usually a dead giveaway for some igneous rock like diabase or basalt. However , these rocks aren't usually the color of yours.
BToo covered with lichens to be definitive but Id say its a red sandstone

C Its a sandstone, we can see the bedding layers

DLooks like a conglomerate but again, its too covered with lichens
F This one is really too coverd to tell accurately

M Layered sandstone or siltstone

S Looks like a siltstone or laminar limestone with quartz lenses in the minor folds

S'-The last one looks like a shale

Better pictures with the pictures taken on a fresh broken surface . If these are rocks around your school yard. Don't break them up. Instead, get a state geology map that includes the area where they come from and see what the geology is listed as. That is a good clue