X (B) is a truncated spur created when the glacier went through the former V shaped valley, truncating its interlocking spurs, to form a U shaped valley.

W is a cirque created when the glacier eroded the side of the mountain via plucking, quarrying, and freeze thaw action to create a basin.

Y is an arete - a knife edged ridge left between two cirques.

Z is a tarn - a lake occupying a cirque.