Because D shells are too big and B shells are too small.
An old shoe... ...and Ronda Rousey
Kids: WE DO! YAY!
Cause the B-shells were too small.
Because she can't fit into D shells
Cause she was too big for B- shells! (my 6 year old niece likes to tell this joke)
Because D-shells are too big and B-shells are too small.